Motifs | Explaining Chess

In the paper, each model gets 100 BP iterations to discover a set of motifs. For the website, we take this further: we started with the Opus 5 motifs, ran 150 more iterations, and continued with other models, including 2,000+ iterations with GLM 5.3 Flash. We keep updating the set as new motifs come in.

MotifΔ (pp)

Material or mobility advantage
+51.3
White to move
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White has 39 legal moves across all pieces; Black has 26. Only each side's most mobile piece or tied pieces are highlighted.
White · most mobile piece Queen on d4: 14 legal moves.
Black · most mobile piece Bishop on c8: 5 legal moves.
Material advantage for the side to move
+48.4
Black to move
1
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8h
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a
Black's extra material outweighs what White has in return.
Black material Black rooks on a8 and h8; Black bishop on c8.
White material White bishops on f1 and d2; White rook on h1.
Compact pawn mass against a splintered enemy skeleton
+45.7
Black to move
1
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8h
g
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a
Black's pawns form 2 islands; White's split into 3. An empty file separates one island from the next.
Black island 1 1 pawns on file a.
Black island 2 4 pawns on files c–e.
White island 1 2 pawns on files b–c.
White island 2 1 pawns on file f.
White island 3 1 pawns on file h.
Bankable extra material with enemy counterplay muted
+43.1
Black to move
1
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7
8h
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b
a
Black has a material lead of 2 points.
Black minor pieces 3 minor pieces.
White minor pieces 4 minor pieces.
Black rooks 2 rooks.
White rooks 1 rooks.
Healthy wing pawn majority
+42.6
Black to move
1
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8h
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a
Black has a usable pawn majority on the highlighted wing.
Black queenside 4 pawns on this wing.
White queenside 2 pawns on this wing.
Positional dominance without material deficit
+34.8
White to move
8
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1a
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White controls the centre more strongly.
Central control The central squares d4, e4, d5, and e5 are occupied or attacked by White.
Controlling the centre White rook on e1; White bishop on d3; White queen on f3; White pawn on d4 contribute to that central control.
Two-file pawn bridgehead wedge or cohesive wall vs stranded pawn
+31.7
White to move
8
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1a
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White has no isolated pawns, while Black does. Look for the gaps beside the isolated pawns, compared with the connected files of White's pawn wall.
White cohesive pawn wall Every pawn has a friendly pawn on a neighboring file.
Black isolated pawns These pawns have no friendly pawn on either neighboring file.
Legal-move freedom surplus over a cramped opponent
+31.0
White to move
8
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1a
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White has 43 legal moves across all pieces; Black has 30. Only each side's most mobile piece or tied pieces are highlighted.
White · most mobile pieces Rook on a1, bishop on f2: 9 legal moves each.
Black · most mobile piece Bishop on e7: 8 legal moves.
Rook or queen on a line with no enemy pieces
+29.0
Black to move
1
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8h
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a
Black's queen on c5 sits on the fifth rank, between the two kings. No White piece occupies that rank.
Fifth rank No White pieces occupy this rank.
Black queen No White piece attacks the queen on c5.
Kings on opposite sides The kings on h1 and g8 lie on opposite sides of the fifth rank.
Central-square control edge with material balance
+27.9
White to move
8
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1a
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White controls 3 of the four central squares; Black controls 2.
White central squares 3 central squares.
Black central squares 2 central squares.
Own king snug in an unpressured shelter
+27.8
Black to move
1
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8h
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b
a
Black's king stays tucked behind its pawn cover, with little enemy pressure nearby.
Sheltered king g8.
Pawn cover f7 and h7.
Connected frontmost pawns
+26.4
White to move
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1a
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h
White has more connected front pawns: 5 against 0.
White connected front pawns Pawns touching another front pawn, with no friendly pawn farther ahead nearby.
Working queen versus benched enemy queen
+23.5
Black to move
1
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8h
g
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b
a
Black's queen has 9 legal moves. White's queen remains on its first two ranks.
Black working queen The queen on d8 has 9 legal moves.
White queen The queen on e2 remains on its first two ranks.
Six-sector positional scoreboard edge
+23.2
White to move
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1a
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White gains two small positional edges: fewer undefended pieces (1 versus 2) and fewer pieces crowding the home ranks (3 versus 4).
White · undefended pieces White's bishop on f4 has no friendly defender.
Black · undefended pieces Black's bishop on g4 and Black's rook on b8 have no friendly defender.
White · pieces near home 3 major or minor pieces remain on the first two ranks: a1, e1, and e2.
Black · pieces near home 4 major or minor pieces remain on the first two ranks: b8, c8, d8, and f8.
Live pawn levers versus a frozen enemy core
+23.0
Black to move
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8h
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a
Black's pawn advances gain more space or create stronger contact.
Black pawns with useful advances All pieces that contribute to this side's score.
White pawns with useful advances All pieces that contribute to this side's score.
Broad quiet dominance scoreboard
+22.3
Black to move
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8h
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a
Black's edge here comes from an open file: 1 rook occupies a pawn-free file, while White has none.
Black · open d-file The rook on d8 occupies a file with no pawns.
Long-range firepower dominance
+20.9
Black to move
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8h
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a
Black has 11 legal moves across rooks and bishops; White has 5. Only each side's most mobile piece or tied pieces are highlighted.
Black · most mobile piece Bishop on b2: 6 legal moves.
White · most mobile piece Rook on d1: 5 legal moves.
Quiet move threatens loose piece
+20.7
Black to move
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8h
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a
Black can play Ne5, which creates new threats.
Move Ne5: c6 to e5.
Targets Enemy pieces attacked after the move.
Permanent holes in the enemy camp
+18.8
Black to move
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8h
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a
Black can use lasting weak squares in White's camp. Enemy pawns on adjacent files cannot advance to drive a piece away from these squares.
Weak square c4 c4 is controlled from c8 and cannot be challenged by an enemy pawn.
Weak square c3 c3 is controlled from a5 and c8 and cannot be challenged by an enemy pawn.
Weak square c2 c2 is controlled from f5 and c8 and cannot be challenged by an enemy pawn.
Weak square d3 d3 is controlled from f5 and cannot be challenged by an enemy pawn.
One-way contact dominance over an untouched army
+18.7
White to move
8
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1a
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White's pieces attack enemy units while Black's non-pawn pieces have no corresponding contact with White's army.
Enemy targets Units attacked by friendly knights, bishops, rooks or queens.
Attacking pieces Pieces applying the one-way contact pressure.
Rook development surplus over sleeping enemy rooks
+17.3
White to move
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White has 2 rooks off their starting squares; Black has 1.
White rooks off their starting squares 2 rooks stand away from their original corners.
Black rooks off their starting squares 1 rooks stand away from their original corners.
Enemy pieces sharing a file
+17.3
Black to move
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a
The a-file contains at least two White pieces or pawns.
Black pieces on the a-file 1 non-king units on this file.
White pieces on the a-file 2 non-king units on this file.
Rank-connected heavy piece coordination edge
+17.2
Black to move
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a
Black's heavy pieces support one another along the same line, forming a battery.
Coordinated heavy pieces e8 and f8 are linked by a clear rank or file.
Pawn storm race lead on the enemy king
+17.2
White to move
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White's pawn storm has reached closer to the enemy king than the opposing storm has reached White's king.
White approaching pawn The pawn on b4 is near the enemy king.
Black approaching pawn The nearest opposing pawn is on f5.
Enemy king The king on e7 faces the closer pawn.
Own king The king on e1 faces the more distant pawn.
Queenless king centralization edge
+17.1
Black to move
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8h
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a
With queens off the board, Black's king stands closer to the center than White's.
Black king The king on c6 is 1.5 squares from the board's midpoint.
White king The king on e1 is 3.5 squares from the board's midpoint.
File-by-file pawn advance lead
+17.1
White to move
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White's pawn front is farther advanced overall, comparing the leading pawn on every file.
White pawn front The most advanced pawn on each occupied file.
Black pawn front The most advanced pawn on each occupied file.
One-way siege of unsupportable enemy pawns
+16.8
Black to move
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8h
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b
a
Black attacks weaknesses in White's pawn structure.
Pawn under pressure Enemy pawns under direct attack.
Attacking pieces These pieces attack the marked pawns.
More undefended enemy pieces than our own
+16.3
Black to move
1
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8h
g
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a
White has 1 undefended piece; Black has 0.
White loose pieces e2.
Centralised army versus a scattered enemy force
+16.0
White to move
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1a
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White's pieces are concentrated closer to the center than Black's.
White army Knights, bishops, rooks and queens in the centralization comparison.
Black army Knights, bishops, rooks and queens in the centralization comparison.
Overall piece mobility edge
+15.7
White to move
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1a
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Adding the attack destinations of non-pawn pieces, including kings, White has 41 against Black's 19; friendly-occupied squares are excluded. Only the pieces with the greatest reach are highlighted.
White · piece with greatest reach Queen on d4: 11 attacked squares without friendly occupants.
Black · piece with greatest reach Queen on c7: 10 attacked squares without friendly occupants.
Crippled enemy minors versus a spotless own minor set
+15.6
Black to move
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8h
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b
a
White has 1 restricted minor piece; Black has none.
Restricted knight The knight on g1 is on an outer two file or reaches at most three squares.
One-sided development tempo: enemy minors still stuck at home
+15.6
Black to move
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8h
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b
a
White has 2 knights or bishops on its first two ranks, compared with 1 for Black.
Black home minors 1 knights or bishops remain on their first two ranks.
White home minors 2 knights or bishops remain on their first two ranks.
One-way projected heavy batteries and open-file monopoly
+15.5
Black to move
1
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8h
g
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b
a
Black has the stronger heavy-piece presence on the open files, without ceding an open file to White.
Black open-file pieces Heavy pieces on completely pawn-free files.
Superior pawn structure and passed pawn edge
+15.4
Black to move
1
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7
8h
g
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b
a
Black's pawns form 2 islands, compared with 3 for White. The opponent's isolated, doubled pawns add another structural weakness.
Black island 1 Pawns on d5, a6, b6, and c7 form one island.
Black island 2 Pawns on h5, f6, and g7 form one island.
White island 1 Pawns on a2 and b5 form one island.
White island 2 Pawns on d3 and d4 form one island. Isolated and doubled on the same file.
White island 3 Pawns on f2, g2, and h4 form one island.
Unopposed active bishop ruling a vacant colour complex
+15.3
Black to move
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b
a
Black has an active bishop on a square color that White no longer has a bishop to contest.
Active bishop The bishop on f5 reaches into the enemy camp.
Bishop's reach Squares reached on this bishop's diagonals.
Unopposed king-approach piece
+15.2
White to move
8
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White's nearest piece is closer to the enemy king: 3 steps versus 5.
White approach The nearest piece is 3 king steps from the opposing king.
Black approach The nearest piece is 5 king steps from the opposing king.
Worst-piece breathing-room mismatch
+15.1
White to move
8
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1a
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Among knights, bishops, rooks and queens, White's least-mobile piece reaches 2 squares without friendly occupants; Black's reaches 0.
White · least-mobile piece Bishop on g5: 2 attacked squares without friendly occupants.
Black · least-mobile piece Bishop on c8: 0 attacked squares without friendly occupants.
Banked exchange or piece bounty
+14.8
White to move
8
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1a
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White has a material lead of 3 points in pieces, excluding pawns.
White minor pieces 3 minor pieces.
Black minor pieces 2 minor pieces.
King breathing room mismatch
+13.6
Black to move
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8h
g
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b
a
Black's king has more open space nearby: 10 empty, enemy-unattacked squares within two squares, versus 3 for White.
Black king The king on e8 is the center of this area.
Black nearby open squares 10 empty, unattacked squares within two king-steps; these are not all immediate king moves.
White king The king on g1 is the center of this area.
White nearby open squares 3 empty, unattacked squares within two king-steps; these are not all immediate king moves.
Unsupported advanced pawn attack
+13.4
Black to move
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8h
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a
Black attacks weaknesses in White's pawn structure.
Pawn under pressure Enemy pawns under direct attack.
Attacking pieces These pieces attack the marked pawns.
Our pieces stand where they cannot be kicked
+13.4
White to move
8
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1a
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h
White's developed pieces are hard to chase: no cheaper enemy unit can hit them now or after a safe move.
Secure pieces f3, b5, and b6.
Enemy king stranded without shelter
+13.1
Black to move
1
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8h
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a
White's king has much less pawn cover than Black's.
Sheltered king Black king on g8; pawn cover on f7, g7, and h7.
Exposed king White king on g2; pawn cover on g3.
Caged enemy rooks versus our deep-breaching rook
+12.2
White to move
8
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White's rook reaches deep into the board while Black's rooks remain confined to their own side.
Active rook The rook on h5 already reaches, or has a rook line toward, the enemy's back three ranks.
Forward reach A square in the enemy's back three ranks on the rook's line.
Restricted enemy rooks These rooks and their current lines remain in their own half.
Exclusive bishop pair with no material deficit
+12.1
White to move
8
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1a
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White has a bishop pair; Black has at most one bishop.
White bishops 2 bishops.
Slider fire on the breached enemy king shield
+12.0
Black to move
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8h
g
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b
a
Black's pieces press the enemy king, with 1 attacked square in its neighborhood.
Black attackers These pieces reach the enemy king's neighborhood.
Pressure squares Squares in the king's neighborhood that those pieces attack.
Enemy king The king on e1 is the focus of the attack.
Cashable pawn: on-the-spot pawn grab that survives the exchange sequence
+11.8
White to move
8
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1a
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White can play Nxf5+, which checks the enemy king.
Move Nxf5+: h4 to f5.
Targets Enemy pieces attacked after the move.
Checked king The move also checks the king on g7.
One-sided artillery barrage on the enemy king zone
+11.7
White to move
8
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1a
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h
White's pieces press the enemy king, with 4 attacked squares in its neighborhood.
White attackers These pieces reach the enemy king's neighborhood.
Pressure squares Squares in the king's neighborhood that those pieces attack.
Enemy king The king on e8 is the focus of the attack.
Attacking force massed close to the enemy king
+11.6
White to move
8
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1a
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h
White has the stronger concentration of attacking pieces near the enemy king.
Pressure around Black's king Pieces on f3, c5, e5, and f6 gather around the king on g7.
Pressure around White's king The piece on c4 gathers around the king on g1.
Slider x-ray pressure through an enemy screen onto a heavier piece
+11.3
Black to move
1
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8h
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b
a
Black's queen stands behind an enemy screen, with the enemy rook farther down the same line.
Rear slider The queen on f6 points down the line.
Screen The piece on b2 stands between the slider and its target.
Target behind the screen The rook on a1 lies on the same line.
Forcing-stroke initiative surplus
+11.2
White to move
8
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1a
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f
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h
White can play Nf6+, which checks the enemy king.
Move Nf6+: e4 to f6.
Targets Enemy pieces attacked after the move.
Checked king The move also checks the king on e8.
Two distant entries into a weakened enemy camp
+11.2
Black to move
1
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8h
g
f
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b
a
Black has two distant entry points into the enemy camp, at least three king-steps apart.
Entry point 1 d4 is an advanced pawn with no enemy pawn ahead nearby.
Entry point 2 h3 is an isolated enemy pawn that can be pressured.
Protected pawn leading the advance
+11.1
Black to move
1
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8h
g
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b
a
Black's defended pawn is farther advanced toward promotion than every enemy pawn.
Leading pawn The pawn on d4 is 3 rank steps from promotion.
Defenders Friendly pieces defend this leading pawn.
Enemy's leading pawns The closest enemy pawns are 4 rank steps from promotion.
Safe piece infiltration in enemy territory
+10.8
White to move
8
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6
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1a
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g
h
White has a secure piece deep in enemy territory. It has useful targets or safe squares available, and enemy pawns cannot easily drive it back.
Secure advanced post White's queen on a8 holds a safe advanced post.
Targets Black bishop on c8 can be attacked from a8.
Pawn-space edge in opponent half
+10.8
White to move
8
7
6
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1a
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f
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h
White's pawns claim more enemy territory: 6 attacks into that half versus 3.
White pawn control 6 pawn attacks into the opponent's half; repeated attacks count separately.
Black pawn control 3 pawn attacks into the opponent's half; repeated attacks count separately.
Advanced pawns d5 has crossed the middle of the board.
Safe fresh-threat move surplus over a silenced opponent
+10.8
Black to move
1
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8h
g
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b
a
Black can play Qc7, which creates new threats.
Move Qc7: d8 to c7.
Targets Enemy pieces attacked after the move.
Enemy army bottled behind the midline under our bridgehead
+10.7
White to move
8
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6
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1a
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h
White has a piece beyond the midline, while no enemy pawn or non-king piece has reached White's first three ranks.
Bridgehead The piece on e5 has crossed into enemy territory.
Pawn-anchored minor entrenched on a permanent deep outpost
+10.6
White to move
8
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4
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1a
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h
White has a pawn-anchored outpost deep in the board.
Outpost Advanced knights or bishops that enemy pawns cannot easily dislodge.
Pawn anchors Pawns supporting the outpost.
Rooks and queens with no friendly pawn ahead
+10.4
Black to move
1
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8h
g
f
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b
a
Black has more rooks or queens with no friendly pawn ahead on their files.
Black rooks and queens 2 rooks or queens have no friendly pawn ahead on their file.
White rooks and queens 1 rooks or queens have no friendly pawn ahead on their file.
Space-gaining pawn wedge in the centre
+10.3
Black to move
1
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5
6
7
8h
g
f
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b
a
Black's pawn on e5 supports the pawn on d4, forming an advanced central chain. Their control of nearby squares leaves White less room to maneuver.
Central pawn chain e5 supports d4.
Space controlled The pawns control c3, e3, and f4 in the enemy half.
Existing double attack by one piece
+10.3
White to move
8
7
6
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4
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1a
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f
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h
One White piece attacks 2 enemy pieces at once.
Attacker White's queen on g3.
Double attack It already attacks d6 and g6.
Opponent starved of forcing resources
+10.1
White to move
8
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1a
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c
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g
h
White's bishop on c1 can move to g5, giving a safe check to Black's king on e7. White has 3 forcing moves, versus 0 for Black.
Key pieces White bishop on c1.
Targets Black king on e7.
Move or pressure square g5.
Queen net
+9.9
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has 5 legal checking moves, compared with 0 for Black. The highlighted pieces are the ones that can give check.
White checking pieces These pieces supply 5 legal checking moves in total.
Clamped enemy queen under one-way pressure
+9.7
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's queen is free to act, while White's queen has only 2 unattacked destinations along its lines.
Black queen The queen on e5 is unattacked and has 18 legal moves.
White queen The queen on f3 has 2 destinations that are neither friendly-occupied nor attacked by Black.
Stranded enemy king or safe double strike
+9.6
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White can play Qe7, which creates new threats.
Move Qe7: c5 to e7.
Targets Enemy pieces attacked after the move.
Passed pawn majority edge
+9.6
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black has more passed pawns: no enemy pawn remains ahead on their file or a neighboring file.
Black passed pawns 1 pawns meet this condition.
Opponent lags in mobilization and king shelter
+9.5
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
Black has knights or bishops on the back rank alongside a less secure king.
Back-rank knights and bishops Black knights on c8 and g8 remain on the back rank.
Awkward king Black's king on f8 also has the less secure placement.
Pressure on weak squares around the enemy king
+9.5
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's pieces concentrate pressure on nearby squares around Black's king. Several have no non-king defender.
Attacking team White bishop on c4; White pawn on f4; White rook on a8 attack squares around the enemy king.
King under pressure Black's king on d7; attacked nearby squares b5, d5, e5, e6, c8, d8, and e8.
Slider battery reinforced and trained on the enemy king
+9.5
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's queen stands behind a friendly screen, with the enemy pawn farther down the same line.
Rear slider The queen on b6 points down the line.
Screen The piece on d4 stands between the slider and its target.
Target behind the screen The pawn on f2 lies on the same line.
Heavy-piece pressure on the enemy pawn rank
+9.4
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's heavy piece attacks pawns on White's second rank.
Attacking heavy piece The rook on b8 reaches the enemy pawn rank.
Pawn-rank targets Enemy pawns on their original pawn rank, attacked along the heavy piece's line.
Free bishop against pawn-strangled enemy bishop
+9.3
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's bishop has open diagonals, while an enemy bishop is hemmed in by its pawn structure.
White bishop The bishop on e3 has 9 unobstructed diagonal squares.
Black bishop The bishop on f8 has 0 unobstructed diagonal squares.
Discovery-fork-initiative
+9.1
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black has more knight-fork opportunities.
Black knights with fork options All pieces that contribute to this side's count.
Black destinations Landing squares counted by the rule.
Pending safe knight fork on the enemy heavy pieces
+8.9
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White can play Nf4, which creates new threats.
Move Nf4: e2 to f4.
Targets Enemy pieces attacked after the move.
Ripe undefended enemy target capturable right now
+8.8
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White can play Nxd5, which captures enemy material.
Move Nxd5: c7 to d5.
Targets Enemy pieces attacked after the move.
Dormant enemy rooks parked on origin squares
+8.8
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
Both Black rooks are on their starting squares.
Rooks on their starting squares Both Black rooks occupy their original corners.
Heavy piece raiding the enemy second rank
+8.7
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's heavy piece can reach the enemy's second rank along an open line, with a pawn target along that rank.
Entry piece The heavy piece on a8 has an unobstructed line to the entry square.
Entry square The empty square a2 is on the enemy's second rank.
Pawn along the rank From the entry square, the line toward c2 is clear.
Pressure on the opponent weak pawns
+8.6
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White can concentrate on a weak enemy pawn.
Weak pawn Black's pawn on b5 is the target.
Attackers White knight on c3; White bishop on c4 attack b5.
Uncontested semi-open rook file
+8.4
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's rook occupies a file with no enemy pawn, rook or queen.
Uncontested rooks h1: no enemy pawn, rook or queen occupies these files.
Central pawn wedge lead
+8.0
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black has more pawns in the central belt: 3 versus 0.
Black central-belt pawns 3 pawns on the c–f files and fourth or fifth ranks.
Two-wing pawn superiority
+8.0
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has a usable pawn majority on the highlighted wing.
White queenside 4 pawns on this wing.
Black queenside 2 pawns on this wing.
Opponent saddled with a bad minor piece
+8.0
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
Black's minor piece is hemmed in by its own pawns.
Restricted minor Black bishop on f8.
Blocking pawns Black pawns on d6 and g7 block its diagonals.
Available square Only e7 remains reachable outside enemy pawn control.
Dynamic pawn levers and safe advances
+7.9
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's pawns offer more useful advances and attacks.
Black pawn play Pawns with useful advances or attacks.
White pawn play Pawns with useful advances or attacks.
Enemy heavy pieces harassed by our lesser units
+7.6
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's pawn on b2 can move to b4, attacking Black's queen on a5 with a cheaper unit.
Threatening move b2 and b4.
Heavy-piece target a5.
Queen mobility mismatch with material balance
+7.6
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's queen attacks or defends 14 squares; Black's attacks or defends 10.
White queen The queen on a6 attacks or defends 14 squares.
Black queen The queen on d8 attacks or defends 10 squares.
Direct contact-count edge
+7.6
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black makes more direct contact with enemy material: 4 attacks versus 0.
Black contacts 4 direct attacks, counting each attacker–target pair.
One-sided pawn shield collapse
+7.3
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's king keeps more pawn shelter, while White's cover has broken down.
Black king The king on g8.
Black shelter Pawns directly ahead of this king.
White king The king on g1.
White shelter Pawns directly ahead of this king.
One-way deep queen berth in the enemy camp
+7.3
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's queen attacks squares around the enemy king, while Black's queen has no corresponding pressure.
Attacking queen The queen on d1 attacks the enemy king's neighborhood.
Pressure near the king Squares beside the king reached by the queen.
Enemy king The king on d7 faces this pressure.
Winning capture with no counter-strike
+7.3
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black can capture the highlighted rook and win a full rook's value. White has no immediate capture of comparable value.
Capturing rook Black rook on d8.
Rook to win White rook on d6.
Coiled discovered attack behind our own screen
+7.3
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's rook stands behind a friendly screen, with the enemy queen farther down the same line.
Rear slider The rook on f8 points down the line.
Screen The piece on f7 stands between the slider and its target.
Target behind the screen The queen on f4 lies on the same line.
Safe checking tempo in hand
+7.3
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White can play Qxe6+, which checks the enemy king.
Move Qxe6+: e2 to e6.
Targets Enemy pieces attacked after the move.
Checked king The move also checks the king on e8.
Connected rooks with enemy rooks split
+7.1
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's rooks can support each other; Black has no connected rook pair.
Connected rooks c1 and d1 share a clear rank.
Black rooks The opponent has no connected rook pair.
Rook lift pressing the enemy king shield
+7.1
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White can play Qf5, which creates new threats.
Move Qf5: d3 to f5.
Targets Enemy pieces attacked after the move.
Concrete exchange-winning capture on a defended enemy piece
+7.0
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black has favorable exchange pressure on the marked piece. This rule's static exchange calculation gives a material gain.
Defended target The piece on d4 is attacked despite having defenders.
Attacking pieces These pieces enter the capture-and-recapture sequence.
Safe queen fork on two enemy units
+7.0
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White can play Qd3, attacking 2 targets at once.
Move White can play Qd3: d1 to d3.
Targets The pieces attacked after the move.
Loaded x-ray battery aimed deep into the enemy camp
+6.9
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's rook stands behind a friendly screen, with the enemy bishop farther down the same line.
Rear slider The rook on f1 points down the line.
Screen The piece on f4 stands between the slider and its target.
Target behind the screen The bishop on f5 lies on the same line.
Cage dominance over an imprisoned enemy piece
+6.9
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
White's piece is hemmed in: its available exits are tightly controlled.
Restricted enemy piece The piece on f1 has very little safe room.
Controlled exits The piece's empty exit squares are covered or restricted.
Punishable caged enemy piece
+6.8
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
Black's piece is hemmed in: its available exits are tightly controlled.
Restricted enemy piece The piece on b8 has very little safe room.
Controlled exits The piece's empty exit squares are covered or restricted.
Safe bishop or rook plunge forming a double attack on a falling target
+6.6
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black can play Rxb2, which captures enemy material.
Move Rxb2: b8 to b2.
Targets Enemy pieces attacked after the move.
Opponent pieces tied to passive defence
+6.6
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Several of White's pieces are tied to defending targets or stopping passed pawns.
Defensive duty White's rook on f1 defends f3.
Defensive duty White's queen on c2 defends c4.
Defensive duty White's knight on a3 defends c4.
Defensive duty White's bishop on d3 defends c4; blockades d4.
Roaming queen dominates a caged enemy queen
+6.6
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's queen has more room along its lines: 14 attack destinations against 6. Friendly-occupied squares are excluded.
White queen The queen on c4 reaches 14 squares without friendly occupants.
Black queen The queen on d8 reaches 6 squares without friendly occupants.
Pawn fork resource
+6.6
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black can play fxe4, attacking 2 targets at once.
Move Black can play fxe4: f5 to e4.
Targets The pieces attacked after the move.
Fewer separated pawn ranks
+6.5
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has fewer groups of adjacent pawn ranks: 1 against 2 for Black.
White rank band 1 Pawns occupy adjacent ranks within this band.
Black rank band 1 Pawns occupy adjacent ranks within this band.
Black rank band 2 Pawns occupy adjacent ranks within this band.
Two-front squeeze against the enemy camp
+6.5
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has pressure on both wings, forcing the defender to attend to two distant fronts.
King-wing pressure Pieces or advanced pawns establishing pressure on the king's wing.
Far-wing target The attacked unit on f4 is on the other wing.
Safe checking resource
+6.4
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White can give check with Rxd5+ while keeping the checking piece defended.
Move White can play Rxd5+: d1 to d5.
Targets The enemy king is checked.
Support The moved piece is defended by e4.
Deep protected spearhead pawn
+6.4
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's defended pawn holds an advanced foothold without being attacked by an enemy pawn.
Advanced pawn The pawn on d4 is on its 5th rank.
Support These friendly pieces defend the advanced pawn.
Advanced decentralized knight outpost
+6.3
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's defended knight has at least five controlled squares and is not attacked by a pawn; White has no equivalent.
Knight outpost d5 is defended.
Support Direct defenders: b6, e6 and d8.
Fully mobilized army against a half-mobilized opponent
+6.3
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has no knights or bishops on the original minor-piece squares. Black still has home pieces to bring into play.
Black home minors 1 knights or bishops remain on the original minor-piece squares.
Queen at home The enemy queen is also on its starting square.
One-sided pins and loaded discovered lines
+6.3
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
White's piece is tied to its king by Black's slider.
Pinned piece The piece on d2 shields its king.
Pinning slider Moving the pinned piece would expose this line.
King behind it The king on e1 is behind the pinned piece.
Ready-made pin and skewer squares for our sliders
+6.2
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's rook on a1 can move to d1, lining up Black's knight on d6 in front of Black's queen on d8.
Slider move a1 and d1.
Front target d6.
More valuable target d8.
Aimed slider battery majority
+6.2
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's queen stands behind a friendly screen, with the enemy knight farther down the same line.
Rear slider The queen on e2 points down the line.
Screen The piece on c4 stands between the slider and its target.
Target behind the screen The knight on a6 lies on the same line.
Multiple attackers on a single weakly defended enemy piece
+6.0
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black outnumbers the defenders of White's highlighted material.
Attackers a8 and d8 apply the pressure.
Under-defended targets a5 has at least two attackers and at most one defender.
Enemy pieces nailed by pins and x-rays
+5.9
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's queen stands behind an enemy screen, with the enemy king farther down the same line.
Rear slider The queen on e5 points down the line.
Screen The piece on e6 stands between the slider and its target.
Target behind the screen The king on e8 lies on the same line.
Side has a connected passed pawn and opponent has none
+5.9
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black has connected passed pawns; White has no connected pair.
Connected passers a6 and b7 are passed pawns on neighbouring files.
Skewer xray winning material
+5.9
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's queen stands behind an enemy screen, with the enemy queen farther down the same line.
Rear slider The queen on f6 points down the line.
Screen The piece on d4 stands between the slider and its target.
Target behind the screen The queen on c3 lies on the same line.
Safe rook or bishop fork on valuable enemy units
+5.9
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White can play Rxd5+, attacking 3 targets at once.
Move White can play Rxd5+: d1 to d5.
Targets The checked king and 2 other targets.
Safe castled wing with opponent king not equally sheltered
+5.8
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black has a castled king with an intact three-pawn shield; White lacks the same shelter.
Black king shelter 3 original shield pawns remain.
White king shelter 1 original shield pawn remains.
Sealed enemy counterplay with banked material and frozen prey
+5.8
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black has a material lead of 1 points.
Black minor pieces 3 minor pieces.
White minor pieces 1 minor pieces.
Black rooks 1 rooks.
White rooks 2 rooks.
Protected pawn chain edge
+5.8
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has more pawns supported by pawns: 2 versus 0 for Black.
White pawns supported by pawns 2 pawns supported by pawns.
Multi-file piece penetration edge
+5.8
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's pieces have entered on 2 files; Black's on 1.
White invaders These pieces occupy 2 different files in the enemy half.
Black invaders These pieces occupy 1 file in the enemy half.
Equal-bishop activity edge
+5.8
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's bishop has more reach: 9 squares versus 3.
Black bishop The bishop whose reach is compared.
Black reach 9 reachable squares outside friendly occupancy.
White bishop The bishop whose reach is compared.
White reach 3 reachable squares outside friendly occupancy.
Pawn structure soreness edge
+5.7
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's pawns form 2 islands; White's split into 3. An empty file separates one island from the next.
Black island 1 2 pawns on files a–b.
Black island 2 4 pawns on files e–h.
White island 1 1 pawns on file a.
White island 2 2 pawns on file c.
White island 3 3 pawns on files f–h.
Loaded discovered battery ready to fire
+5.6
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's bishop stands behind a friendly screen, with the enemy pawn farther down the same line.
Rear slider The bishop on e3 points down the line.
Screen The piece on d4 stands between the slider and its target.
Target behind the screen The pawn on b6 lies on the same line.
Deep-penetration assets: seventh-rank heavyweight or near-queening passer
+5.6
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's rook or queen has reached deep into the enemy camp and creates pressure from there.
Invading heavy piece The queen on h7 is inside enemy territory.
Enemy targets Pieces attacked by the invader.
Discovered attack lined up behind our own screen
+5.5
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's rook stands behind a friendly screen, with the enemy pawn farther down the same line.
Rear slider The rook on h8 points down the line.
Screen The piece on h7 stands between the slider and its target.
Target behind the screen The pawn on h2 lies on the same line.
Unassailable advanced pawn wedge
+5.5
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has more protected pawns across the midline with no clear path for an enemy pawn to attack them.
White protected wedge pawns All pieces that contribute to this side's count.
Pin or skewer xray
+5.4
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's queen stands behind an enemy screen, with the enemy king farther down the same line.
Rear slider The queen on a6 points down the line.
Screen The piece on d3 stands between the slider and its target.
Target behind the screen The king on e2 lies on the same line.
Queen harasses more enemy units than enemy queen harasses ours
+5.3
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's queen attacks more enemy units: 2 versus 0.
Black queen Attacks 2 enemy units.
Black targets The enemy units this queen attacks.
White queen Attacks 0 enemy units.
One-way standing double strike or queen liberty mismatch
+5.3
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black has more ready double attacks than White, with valuable or undefended targets among them.
Black double attackers Safe pieces attacking at least two enemy units.
Black simultaneous targets Targets attacked by these double attackers.
Free landing squares across the frontier
+5.3
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black has more uncontested landing squares across the midline: 4 against 1.
Black entry pieces These pieces have quiet moves across the midline.
Black free landing squares Empty enemy-half squares that are not currently attacked by the enemy.
White entry pieces These pieces have quiet moves across the midline.
White free landing squares Empty enemy-half squares that are not currently attacked by the enemy.
Buried enemy queen
+5.3
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
White's queen has only 2 unattacked destinations along its lines.
Restricted queen The queen on f3 has 2 destinations that are neither friendly-occupied nor attacked by Black.
Unattacked destinations The remaining destinations along the queen's lines that are not attacked.
Safe knight fork on a king, queen, or rook
+5.3
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black can play Nc2, attacking 2 targets at once.
Move Black can play Nc2: b4 to c2.
Targets The pieces attacked after the move.
Queenless endgame regimen edge
+5.3
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's king sits closer to the centre of its own pawn group, and its best rook reaches 8 empty squares versus Black's 2.
White · king and pawns The king is closer to the centre of its own pawn group.
Black · king and pawns The king is farther from the centre of its own pawn group.
White · rook reach The rook on d1 reaches 8 highlighted empty squares.
Black · rook reach The rook on e8 reaches 2 highlighted empty squares.
Seventh-rank heavy invasion or absolute-pin surplus
+5.2
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's rook or queen has reached deep into the enemy camp and creates pressure from there.
Invading heavy piece The queen on a1 is inside enemy territory.
Enemy targets Pieces attacked by the invader.
One-move safe entries into the enemy half
+5.2
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has more ways to advance: 2 moves versus 0.
White advance options 2 moves into enemy territory: Bxe5, Ba5+.
Protected advanced pawn wedge
+5.2
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has a defended pawn in enemy territory, outside enemy pawn attacks; Black has no equivalent.
Supported advance e5 is defended.
Support Direct defenders: g3.
Pending tactic tips the material balance
+5.1
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's bishop on b7 can capture White's rook on h1. The exchange estimate is a gain of 2 material points, enough to put Black ahead.
Capturing piece b7.
Tactical gain h1.
Advanced outside pawn majority
+5.1
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has a 4–3 pawn majority on the queenside, away from the enemy king.
White queenside 4 pawns on this wing.
Black queenside 3 pawns on this wing.
Enemy king The comparison uses the opposite wing.
Playable pawn majority on the wing away from the enemy king
+5.1
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black has a usable pawn majority on the highlighted wing.
Black queenside 4 pawns on this wing.
White queenside 2 pawns on this wing.
Safe king mobility edge
+5.1
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's king has more room: 3 safe squares versus 0.
White king Has 3 safe neighbouring squares.
White king destinations Adjacent squares not attacked in this position.
Black king Has 0 safe neighbouring squares.
Attacking pawn majority around enemy king
+5.1
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has a 4–3 pawn majority on the kingside.
White kingside 4 pawns on this wing.
Black kingside 3 pawns on this wing.
Enemy king The comparison uses the king's wing.
Permanent piece blockade of enemy pawns
+5.1
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has 1 secure pawn blockade, compared with 0 for Black. Each blockader stops an enemy pawn on a square no enemy pawn can chase it from.
White blockaders h5.
Stopped enemy pawns h6.
Knight mobility edge
+5.0
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's knights have more reach: 10 squares versus 0.
White knights The knights whose reach is compared.
White reach 10 controlled squares, including friendly-occupied squares.
Netted enemy passed pawns
+4.9
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Each White passed pawn has a specific obstacle: a blockade, direct pressure, or control of its advance or promotion square.
Enemy passed pawns These pawns have no opposing pawn ahead on their own or neighboring files.
Occupied promotion square A friendly piece occupies the promotion square.
Deep pawn-shielded knight outposts unchallenged by enemy pawns
+4.9
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black has a pawn-anchored outpost deep in the board.
Outpost Advanced knights or bishops that enemy pawns cannot easily dislodge.
Pawn anchors Pawns supporting the outpost.
Loaded discovered attack down an open line
+4.9
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's rook stands behind a friendly screen, with the enemy queen farther down the same line.
Rear slider The rook on d1 points down the line.
Screen The piece on d4 stands between the slider and its target.
Target behind the screen The queen on d6 lies on the same line.
Coiled discovered attack behind our own vanguard
+4.9
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's rook stands behind a friendly screen, with the enemy bishop farther down the same line.
Rear slider The rook on f7 points down the line.
Screen The piece on f6 stands between the slider and its target.
Target behind the screen The bishop on f4 lies on the same line.
Opponent moves keep walking into loss of material
+4.8
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
If White's knight on f3 moves to g5, Black's pawn on f6 attacks it there.
Key pieces Black pawn on f6.
Targets White knight on f3.
Move or pressure square g5.
King-front pawn wedge against a sealed enemy camp
+4.7
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's defended pawn has advanced beside the enemy king, while enemy units have not reached White's first three ranks.
Advanced pawn The pawn on f6 is on its 6th rank.
Support These friendly pieces defend the advanced pawn.
Enemy king The advanced pawn is on the king's file or a neighboring file.
Quiet double threat while opponent has no free capture
+4.7
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black can play Nb6, which creates new threats.
Move Nb6: d5 to b6.
Targets Enemy pieces attacked after the move.
Pawn-protected pieces versus hanging enemy pieces
+4.7
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's pawn-supported pieces contrast with White's undefended pieces.
Pawn-supported pieces 2 Black pieces are protected by pawns.
Undefended enemy pieces 2 White pieces have no defenders.
Rook or queen on a passed pawn's file
+4.7
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's rook on b8 stands behind its own passed pawn on b5, with no piece between them.
Black passed pawn No White pawn is ahead on this file or either neighboring file.
Rook behind pawn No piece stands between b8 and b5.
Protected minor piece outpost without opponent equivalent
+4.7
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black has a defended minor piece in enemy territory, outside enemy pawn attacks; White has no equivalent.
Supported advance c3 is defended.
Support Direct defenders: b5.
Quiet double-lever threat machine
+4.6
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White can play Rd6, which creates new threats.
Move Rd6: d1 to d6.
Targets Enemy pieces attacked after the move.
Protected central wedge pawn beyond the midline
+4.6
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's central pawn has crossed the midline and is backed by another pawn.
Advanced pawn The pawn on e4 is on its 5th rank.
Pawn support These friendly pieces defend the advanced pawn.
Seventh-rank invasion lever
+4.4
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has safe heavy-piece entries onto the enemy's second rank, creating threats along that rank.
White entry pieces Rooks or queens with an entry to the opponent's second rank.
White landing squares Safe invasion squares counted by the motif.
Black entry pieces Rooks or queens with an entry to the opponent's second rank.
Black landing squares Safe invasion squares counted by the motif.
Heavy file pressure on an isolated or doubled enemy pawn
+4.4
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White attacks weaknesses in Black's pawn structure.
Pawn under pressure Enemy pawns under direct attack.
Attacking pieces These pieces attack the marked pawns.
Open invasion routes into the enemy camp
+4.4
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
One open invasion route: Black's queen on e6 can reach the undefended square e1 deep in White's camp.
Invading piece e6.
Entry square e1.
Enemy pawn over-extended into our camp
+4.4
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
White's advanced pawn has become a target instead of a strength. It lacks neighboring pawn support, and its next step is controlled by the opponent.
Weak pawn White's pawn on d5 has no neighboring pawn support.
Attackers Black queen on d7 attack d5.
Blocked advance d6 is more strongly controlled by Black.
Piling up on a pinned or x-rayed enemy piece
+4.4
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
Black's knight on d6 is lined up in front of Black's king on c7. White piles pressure onto this tied-down target.
Attacking pieces f4.
Pinned or x-rayed target d6.
Piece behind it c7.
Unmasking battery threat on king, queen or rook
+4.2
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White can play Bd7+, which checks the enemy king.
Move Bd7+: h3 to d7.
Checked king The move also checks the king on e8.
Cocked discovery: own screen masks a loaded slider
+4.2
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's rook stands behind a friendly screen, with the enemy bishop farther down the same line.
Rear slider The rook on c1 points down the line.
Screen The piece on c7 stands between the slider and its target.
Target behind the screen The bishop on c8 lies on the same line.
Guarded minor piece prowling the enemy king ring
+4.1
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's piece presses the squares around White's king.
Attacker Black's bishop on c7.
King pressure Controls h2 beside White's king.
Support e6 and d7 defend the attacker.
Crushing file fire on a landlocked backward enemy pawn
+4.1
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White attacks weaknesses in Black's pawn structure.
Pawn under pressure Enemy pawns under direct attack.
Attacking pieces These pieces attack the marked pawns.
Major piece on a semi-open file next to the enemy king
+4.0
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's heavy piece has a pawn-free approach beside Black's king.
Open approach d1: these files have no friendly pawns.
Enemy king The files lie on or beside the enemy king's file.
Enemy minors still parked on their starting squares
+4.0
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
Black has 2 knights or bishops on original minor-piece squares, compared with 0 for White.
Black home minors 2 knights or bishops remain on the original minor-piece squares.
Pawn-protected piece superiority
+3.9
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has more pawn-protected pieces: 2 versus 0 for Black.
White pawn-protected pieces 2 pawn-protected pieces.
Opponent burdened with two different kinds of weakness
+3.8
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
White has two weaknesses: a backward pawn and an exposed king.
Backward pawn White pawns on d4 and e5 show the lagging pawn and its advanced neighbor.
Exposed king White's king on e1 has no nearby pawn shelter.
Knight pressure on the enemy king ring
+3.8
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's piece presses the squares around Black's king.
Attacker White's knight on e5.
King pressure Controls g6 beside Black's king.
Decisive pawn promotion race lead
+3.8
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's leading pawn is much closer to promotion than the enemy's leading pawn.
White leading pawns The most advanced pawns are on relative rank 5.
Black leading pawns The most advanced pawns are on relative rank 2.
Covered pawn wall against defenseless enemy pawns
+3.7
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black has fewer completely undefended pawns than White, giving its pawn wall better support.
Black undefended pawns Pawns with no friendly defender.
White undefended pawns Pawns with no friendly defender.
Piece development lead
+3.7
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black has 4 pieces off their starting squares; White has 1.
Black developed pieces 4 pieces away from their usual starting squares.
White developed pieces 1 piece away from their usual starting squares.
Safe defended pressure on king flight squares
+3.6
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's defended pieces restrict White's king by controlling 2 neighbouring squares.
Defended attackers Each attacker is defended and cannot be captured by an enemy pawn.
Controlled king-neighbour squares 2 squares beside the enemy king are controlled.
Enemy king The controlled squares lie next to this king.
Favorable piece imbalance without a material lead
+3.6
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has more minor pieces in exchange for fewer rooks. The different armies have roughly equal material.
White material White rook on a1; White pawns on a2, b2, h2, d3, g3, c4, and f4; White knights on g2 and c3; White bishop on e3.
Black material Black pawns on a5, e5, f5, b6, d6, c7, g7, and h7; Black knight on c5; Black rooks on e8 and f8.
Profitable target pressure differential
+3.6
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has favorable exchange pressure on a bishop, while Black's corresponding target is a pawn.
White profitable targets Bishop on e7: favorable capture-and-recapture balance.
Black profitable targets Pawn on d3: favorable capture-and-recapture balance.
Checking capture
+3.5
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black can capture with Rxd1+ and give check at the same time.
Move Black can play Rxd1+: d4 to d1.
Targets The enemy king is checked.
One-colour-complex monopoly after the enemy bishop trade
+3.5
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has an active bishop on a square color that Black no longer has a bishop to contest.
Active bishop The bishop on e3 reaches into the enemy camp.
Bishop's reach Squares reached on this bishop's diagonals.
Grip on the opponent weak colour complex
+3.4
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has a bishop of a color the opponent cannot match. Its grip on that color's weak squares gives the opponent a lasting defensive problem.
Established pieces White bishop on b2; White pawns on b4 and d6 establish the grip on this color.
Weak squares controlled The bishop controls d4 and e5, which enemy pawns cannot protect.
Central-file heavy piece without contest
+3.4
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has a rook or queen on a central file; Black has neither on those files.
Central heavy pieces d4 occupies the d- or e-file.
Quiet royal check with king-space edge
+3.2
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
The quiet check Ng3+ leaves White's king fewer moves: 1 versus 2 for Black's king now.
Checking move Black can play Ng3+ without capturing.
White king 1 legal king reply after the check.
Black king 2 legal king moves before the check.
Heavy piece backing an advanced pawn
+3.2
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's heavy pieces share files with advanced pawns.
Heavy pieces Rooks or queens sharing the advanced pawns' files.
Advanced pawns Pawns already across the middle of the board.
Central cramping pawn bind freezing the enemy centre
+3.2
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's pawn blocks an enemy pawn head-on, with a friendly pawn supporting the bind.
Advanced pawn The pawn on d5 is on its 5th rank.
Pawn support These friendly pieces defend the advanced pawn.
Blocked enemy pawn This enemy pawn is directly in front and cannot advance.
True material edge hidden without a visible lead
+3.1
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's extra material outweighs what White has in return.
Black material Black pawns on c5, a7, f7, g7, and h7; Black rooks on a6 and f8.
White material White rook on a1; White pawns on a2, b2, f2, h2, g3, and c4; White knight on c3.
Intact shield siege on a stripped enemy king
+3.1
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's king keeps more pawn shelter, while White's cover has broken down.
Black king The king on g8.
Black shelter Pawns directly ahead of this king.
White king The king on f2.
White shelter Pawns directly ahead of this king.
Pawn-defended attacker near enemy king
+3.1
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's piece presses the squares around Black's king.
Attacker White's queen on b3.
King pressure Controls b7 and b8 beside Black's king.
Support a2 and c2 defend the attacker.
Minor-piece check with a second target
+3.0
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black can play Nf4+, attacking 2 targets at once.
Move Black can play Nf4+: d5 to f4.
Targets The checked king and 1 other target.
Support The moved piece is defended by f8.
Heavy-piece defended pawn advance into opponent half
+3.0
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's pawn can advance into enemy territory with rook or queen support.
Pawn advance White can play h5 into the enemy half.
Heavy-piece support h1 defends the pawn after it advances.
Enemy queen hemmed in under fire with our own queen breathing free
+3.0
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
Black's queen has only 3 unattacked destinations along its lines.
Restricted queen The queen on e7 has 3 destinations that are neither friendly-occupied nor attacked by White.
Unattacked destinations The remaining destinations along the queen's lines that are not attacked.
Exclusive pawn breakthrough superiority
+3.0
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has more pawn breakthroughs: the counted advances create an additional passed pawn or reach promotion.
White pawns with breakthrough options All pieces that contribute to this side's count.
White destinations Landing squares counted by the rule.
Artillery-loaded pawn break
+2.9
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White can play d5, which creates new threats.
Move d5: d4 to d5.
Queen check with a side target
+2.9
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black can play Qxf2+, attacking 4 targets at once.
Move Black can play Qxf2+: f6 to f2.
Targets The checked king and 3 other targets.
One-way pawn power: deep breach, riding passer or rolling phalanx
+2.9
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's advanced pawn stands farther forward than the enemy pawn front.
Advanced pawns Pawns holding space in enemy territory.
Pawn support Pawns supporting that advanced foothold.
Loaded queen-backed battery charging the enemy king
+2.8
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's rook stands behind a friendly screen, with the enemy pawn farther down the same line.
Rear slider The rook on f8 points down the line.
Screen The piece on f5 stands between the slider and its target.
Target behind the screen The pawn on f2 lies on the same line.
Sustained pressure on defended enemy units
+2.8
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
Black's pawn on f7 is defended but remains under pressure: 2 attackers outnumber its 1 defender.
Attacking pieces b3 and e5.
Pressure target f7.
Defenders e7.
Pawn storm against the castled enemy king
+2.8
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's advanced pawns bear down on Black's castled king.
Pawn storm g4 and f5.
King shelter f6, f7, and g8.
Castling rights lead
+2.8
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black retains both castling rights; White retains no castling rights.
Black castling rights Kingside, queenside.
White castling rights No castling rights remain.
Doubled heavy-file ram on a pawn-free file
+2.8
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's heavy pieces support one another along the same line, forming a battery.
Coordinated heavy pieces e6 and e8 are linked by a clear rank or file.
Encircled enemy king with sealed flight squares
+2.8
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's pieces press the enemy king, with 4 attacked squares in its neighborhood.
Black attackers These pieces reach the enemy king's neighborhood.
Pressure squares Squares in the king's neighborhood that those pieces attack.
Enemy king The king on f2 is the focus of the attack.
Stranded never-castled enemy king behind a broken shell
+2.7
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
Black's king is stranded near the center with no castling rights. White's king has left its home central files.
White king This king is already away from its home central files.
Black stranded king This king remains on its home central files with no castling rights.
Remaining enemy shelter Only 2 shield pawns remain on the nearby files and first two pawn ranks.
Protected minor attack on a pawn-uncovered enemy piece
+2.7
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's supported piece attacks White's highlighted material.
Attacking piece Black's knight on f6.
Targets It attacks e4.
Support The attacker is defended by g7.
More permanent cracks in the enemy camp
+2.7
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
White's camp has more persistent weaknesses than Black's. Each color shows one counted kind of weakness.
White restricted minors Rim knights or bishops with very short diagonals.
White vulnerable pawns Attacked pawn defects without a pawn defender.
Black vulnerable pawns Attacked pawn defects without a pawn defender.
Army surplus with a crushing check in hand
+2.6
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black has more knights, bishops, rooks and queens still on the board: 4 against 3.
Black minor pieces 3 minor pieces.
White minor pieces 1 minor pieces.
Black rooks 1 rooks.
White rooks 2 rooks.
Advanced knight harassing enemy pieces
+2.6
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's advanced knight attacks White's highlighted material.
Attacking piece Black's knight on e3.
Targets It attacks g2.
Protected advanced piece hitting an enemy pawn
+2.6
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's supported piece attacks Black's pawns.
Attacking piece White's knight on g5.
Targets It attacks f7 and h7.
Support The attacker is defended by f4.
Enemy royals already netted
+2.6
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black can play Bh4+, checking from a square near the enemy king that no enemy piece currently attacks.
Move Bh4+: f6 to h4.
Checked king The move also checks the king on f2.
One-move discovered attack on queen, rook, or king
+2.6
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
A friendly screen hides White's line of attack.
Rear attacker White's rook on f1.
Friendly screen f4 is the only piece blocking the line.
X-ray target The line points at Black's queen on f7.
Enemy camp riddled with concrete pressure points
+2.6
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has more attackers than defenders against this pawn.
Weak pawn Black's pawn on g5 is the target.
Attackers White bishop on c1; White pawn on h4 attack g5.
Defender Black pawn on h6 defend g5.
Castling-rights tempo lock on a centre-stranded rival king
+2.5
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
Black's king is stranded near the center with no castling rights. White still retains castling rights.
White king This side retains castling rights.
Black stranded king This king remains on its home central files with no castling rights.
Undeveloped enemy minors These knights or bishops still occupy their starting squares.
Deep enemy piece outnumbered in our camp
+2.4
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
White's advanced pieces are outnumbered by Black's attackers.
Invading targets d5 lies in Black's half, with more attackers than defenders.
Attackers The friendly force pressuring the invaders.
Blockaded isolated enemy pawn under rook-file fire
+2.4
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White attacks weaknesses in Black's pawn structure.
Pawn under pressure Enemy pawns under direct attack.
Attacking pieces These pieces attack the marked pawns.
Overloaded enemy defender with two attacked wards
+2.4
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
Black's defender has more than one job: it is protecting several pieces already under attack.
Shared defender The piece on d8 supports several attacked units.
Its defensive duties These attacked pieces depend on the same defender.
Pawn-led material ambush and knight fork geometry
+2.4
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black can play Ng3+, which checks the enemy king.
Move Ng3+: h5 to g3.
Targets Enemy pieces attacked after the move.
Checked king The move also checks the king on h1.
Loaded battery bearing on the enemy king
+2.4
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's queen stands behind a friendly screen, with the enemy knight farther down the same line.
Rear slider The queen on e6 points down the line.
Screen The piece on d5 stands between the slider and its target.
Target behind the screen The knight on c4 lies on the same line.
Enemy pieces pinned under our slider x-ray
+2.4
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
Black's piece is tied to its king by White's slider.
Pinned piece The piece on f6 shields its king.
Pinning slider Moving the pinned piece would expose this line.
King behind it The king on f8 is behind the pinned piece.
One sided pressure on chronically weak enemy pawns
+2.4
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black attacks weaknesses in White's pawn structure.
Pawn under pressure Enemy pawns under direct attack.
Attacking pieces These pieces attack the marked pawns.
Aligned slider battery
+2.3
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has two long-range pieces aligned with no piece between them; Black has no equivalent battery.
Aligned battery a1 and f1 share clear lines.
Overloaded enemy defender stretched across two falling targets
+2.3
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
White's defender has more than one job: it is protecting several pieces already under attack.
Shared defender The piece on d1 supports several attacked units.
Its defensive duties These attacked pieces depend on the same defender.
Loaded battery aimed at the enemy camp
+2.3
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's rook stands behind a friendly screen, with the enemy pawn farther down the same line.
Rear slider The rook on f1 points down the line.
Screen The piece on f4 stands between the slider and its target.
Target behind the screen The pawn on f7 lies on the same line.
Quiet discovered attack unveiling a rear slider onto valuable prey
+2.3
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White can play Bb6, which creates new threats.
Move Bb6: e3 to b6.
Targets Enemy pieces attacked after the move.
Uncovered targets Targets reached when the line opens.
Uncovered slider The move clears this slider's line.
Knight one move from a sealed deep outpost
+2.2
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White can play Nd5, which creates new threats.
Move Nd5: c3 to d5.
Targets Enemy pieces attacked after the move.
One-way durable king-pin pressure on enemy officers
+2.2
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
Black's piece is tied to its king by White's slider.
Pinned piece The piece on f6 shields its king.
Pinning slider Moving the pinned piece would expose this line.
King behind it The king on f8 is behind the pinned piece.
Overloaded sole enemy defender under dual pressure
+2.2
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
Black's defender has more than one job: it is protecting several pieces already under attack.
Black stretched defenders Each is the sole non-king defender of at least two attacked units.
Shared defender The piece on b6 supports several attacked units.
Its defensive duties These attacked pieces depend on the same defender.
Loaded discovery lines behind own pieces
+2.2
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's pawn on d4 can capture on c5, letting White's rook on d3 attack Black's rook on d6.
Hidden slider d3.
Move aside d4 and c5.
Discovered target d6.
Enemy pieces idling behind their own lines
+2.2
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
Black's highlighted pieces sit passively inside their own half, with no enemy targets or attacked friends to support.
Black idle pieces a6 and g7.
Outside queenside pawn majority with castled kings
+2.1
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has a 3–2 pawn majority on the queenside.
White queenside 3 pawns on this wing.
Black queenside 2 pawns on this wing.
White king and shelter Both kings are on the kingside; these pawns shelter the friendly king.
Black king and shelter The opposing king is on the kingside.
One-way material-winning pressure board
+2.1
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black can play Nb4, which creates new threats.
Move Nb4: c6 to b4.
Targets Enemy pieces attacked after the move.
One-sided crossfire on enemy pieces and free pawns
+2.1
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black puts pressure on more enemy targets than White does: 2 against 0.
Black targets Enemy units under direct attack.
Multiple safe checks with material edge
+2.0
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black can play Qe3+, which checks the enemy king.
Move Qe3+: d4 to e3.
Targets Enemy pieces attacked after the move.
Checked king The move also checks the king on e1.
Opponent pieces cornered and hanging
+2.0
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
Black's highlighted piece has no safe move.
Restricted piece Black's bishop on f8 has no safe destination in this position.
Ready demolition capture against the enemy king shelter
+2.0
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White can play Nxf5+, which checks the enemy king.
Move Nxf5+: h4 to f5.
Targets Enemy pieces attacked after the move.
Checked king The move also checks the king on g7.
Healthy wing pawn majority away from the enemy king
+2.0
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has a healthy queenside pawn majority: 2 pawns against 1. The pawns occupy more files and have room to advance.
White majority a2 and b3.
Black pawns on this wing a5.
Major piece dominates the squares next to the enemy king
+1.9
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's piece presses the squares around Black's king.
Attacker White's queen on h6.
King pressure Controls g7, h7 and h8 beside Black's king.
Net piece-to-piece pressure surplus
+1.9
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black puts pressure on more enemy targets than White does: 2 against 0.
Black targets Enemy units under direct attack.
Safe pawn grab advantage
+1.9
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White can play cxd5, which captures enemy material.
Move cxd5: c4 to d5.
Central queen against a king that has lost castling rights
+1.9
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's central queen faces a king that has lost both castling rights.
Central queen c5 is in the central sixteen squares.
Enemy king No castling rights remain.
Tempo-gaining threat creation dominance
+1.8
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's queen on d8 can move to c7, safely creating an attack on White's bishop on c6, which was not attacked before.
Key pieces Black queen on d8.
Targets White bishop on c6.
Move or pressure square c7.
Enemy queen nailed to lone defense
+1.8
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
Black's queen is tied to defending an attacked pawn or minor piece.
Target The pawn or minor on f7 depends on the queen's protection.
Only defenders Only enemy queens defend this target.
Pressure Pieces applying pressure to the target.
Major-piece lamplight on an undefendable enemy pawn with clean own structure
+1.8
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White attacks weaknesses in Black's pawn structure.
Pawn under pressure Enemy pawns under direct attack.
Attacking pieces These pieces attack the marked pawns.
Deep conversion asset: seventh-rank heavy or connected passers
+1.7
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's rook or queen has reached deep into the enemy camp and creates pressure from there.
Invading heavy piece The queen on h7 is inside enemy territory.
Enemy targets Pieces attacked by the invader.
Opposite wing pawn storm with a shielded home king
+1.7
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
The kings are on opposite wings, and White has a pawn storm aimed at the enemy king.
Pawn storm Pawns on the enemy king's wing.
Enemy king The king on c7 faces this pawn storm.
Own king The king on h2 is on the other wing.
Loaded battery sighted on the enemy king
+1.7
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's rook stands behind a friendly screen, with the enemy pawn farther down the same line.
Rear slider The rook on d1 points down the line.
Screen The piece on d5 stands between the slider and its target.
Target behind the screen The pawn on d7 lies on the same line.
Loaded heavy-piece battery on one line
+1.7
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's heavy pieces support one another along the same line, forming a battery.
Coordinated heavy pieces c8 and f8 are linked by a clear rank or file.
Queen mobility edge
+1.7
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's queen has more legal destinations: 16 versus 9.
Black queen The queen whose mobility is compared.
Black queen destinations 16 legal destination squares.
White queen The queen whose mobility is compared.
White queen destinations 9 legal destination squares.
Heavy siege on a frozen lone pawn on a half-open file
+1.7
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black attacks weaknesses in White's pawn structure.
Pawn under pressure Enemy pawns under direct attack.
Attacking pieces These pieces attack the marked pawns.
Fianchettoed bishop support
+1.7
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's bishops are fianchettoed behind their wing pawns.
Fianchetto Bishop on g2, behind the pawn on g3.
Fianchetto Bishop on b2, behind the pawn on b3.
Invasion piece on the seventh rank
+1.6
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's piece has penetrated to the seventh rank.
Seventh-rank invaders a7 has reached the rank just before the enemy back rank.
Overloaded defender facing scattered attacks
+1.6
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
One Black defender is tied to two attacked pieces.
Attacked targets c5 and e6 are attacked by different friendly pieces.
Shared defender d6 is their sole shared non-pawn defender.
Attackers b4 and d4 create the two threats.
Standing siege of the luft-less enemy castle
+1.6
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White presses an enemy king that remains boxed on its home rank.
Heavy-piece pressure The heavy piece on c7 reaches the enemy king's home rank.
Confined king The king on g8 has no pawn-made escape.
Ready discovered-attack x-ray on an enemy heavy piece
+1.5
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's queen stands behind a friendly screen, with the enemy queen farther down the same line.
Rear slider The queen on f5 points down the line.
Screen The piece on e5 stands between the slider and its target.
Target behind the screen The queen on d5 lies on the same line.
Pinned-and-hanging with armed royal forks
+1.5
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White can play Ne6, which creates new threats.
Move Ne6: c7 to e6.
Targets Enemy pieces attacked after the move.
Rear-rank piece pressure edge
+1.5
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White attacks more pieces on the enemy back rank: 1 versus 0.
White attacked back-rank pieces 1 attacked back-rank piece.
Clean undoubled pawns while opponent is doubled
+1.5
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has no doubled pawns; Black does.
Doubled enemy pawns f6 and f7 share files.
Undoubled friendly pawns Every friendly pawn occupies a different file.
Unopposed long-diagonal bishop aimed at the enemy king
+1.5
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black's piece presses the squares around White's king.
Attacker Black's bishop on c6.
King pressure Controls f3 beside White's king.
Heavy-piece geometry on the enemy first two ranks
+1.5
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's rook or queen has reached deep into the enemy camp and creates pressure from there.
Invading heavy piece The queen on h7 is inside enemy territory.
Enemy targets Pieces attacked by the invader.
Advanced pawn option edge
+1.5
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has more ways to advance: 3 moves versus 1.
White advance options 3 moves into enemy territory: hxg6, h6, d5.
Black advance options 1 move into enemy territory: a3.
Connected promotion ladder passers
+1.5
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's protected passed pawn is close to promotion, with no enemy pawn left ahead of it.
Near-promotion passer The pawn on d6 is at most two pushes from promotion.
Support Friendly pieces support the advanced pawn.
Far advanced pawn in opponent half
+1.5
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's pawn has reached the sixth rank, close to promotion.
Far-advanced pawns h6 is on the sixth rank or beyond.
Queen-rook file coordination edge
+1.4
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's queen and rook are coordinated; Black has no matching arrangement.
Queen–rook coordination a1 and a4 share a file.
Black heavy pieces No opposing queen–rook pair shares a file.
Connected queen-rook battery versus unconnected enemy heavies
+1.4
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's queen and rook are coordinated; Black has no matching arrangement.
Queen–rook coordination e3 and f3 defend one another on a clear line.
Black heavy pieces No opposing heavy-piece pair defends one another.
Caged counterplay: lone queen sway or blockaded passing lane
+1.4
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Each White passed pawn has a specific obstacle: a blockade, direct pressure, or control of its advance or promotion square.
Enemy passed pawns These pawns have no opposing pawn ahead on their own or neighboring files.
Blockader This defended non-king piece occupies the passer's next square.
Minor-piece fork resource on enemy minor pieces
+1.3
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White can play Bf3, attacking 2 targets at once.
Move White can play Bf3: e2 to f3.
Targets The pieces attacked after the move.
Heavy piece aligned with enemy king
+1.3
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's rook or queen lines up with Black's king.
Aligned heavy pieces e2 shares a rank or file with the enemy king.
Enemy king The king shares a rank or file with the highlighted heavy piece.
Enemy minor marooned in our camp
+1.3
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
White's piece is hemmed in: its available exits are tightly controlled.
Restricted enemy piece The piece on g2 has very little safe room.
Controlled exits The piece's empty exit squares are covered or restricted.
One-move-away covered fork on enemy heavy pieces
+1.3
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White can play Nc6, which creates new threats.
Move Nc6: e5 to c6.
Targets Enemy pieces attacked after the move.
Healthy pawn-break monopoly
+1.3
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White can play f4, which creates new threats.
Move f4: f3 to f4.
Pawn persecution of enemy minors
+1.3
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White has more pawn-pressure opportunities against enemy knights and bishops, including immediate pawn advances.
White pawn pressure Pawns already attacking minors or ready to advance against them.
White advance squares A pawn advance to these squares attacks a minor piece.
White minor-piece targets Knights or bishops affected by the pawn pressure.
Safe rook fork on two enemy units
+1.3
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White can play Rd7, attacking 2 targets at once.
Move White can play Rd7: c7 to d7.
Targets The pieces attacked after the move.
Open slider lines drilling into the castled enemy king
+1.2
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's sliders aim along pawn-free lines toward Black's king.
Aimed sliders g2 and f4.
King-zone endpoints Squares beside the king where the pawn-free lines lead.
Heavy battery on the enemy king file or second rank
+1.2
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's heavy pieces occupy a useful invasion line against the enemy camp.
Heavy-piece foothold Heavy pieces on the enemy king file or second rank.
Enemy king The king on g8 faces this pressure.
Protected central bishop with forward range
+1.1
White to move
8
7
6
5
4
3
2
1a
b
c
d
e
f
g
h
White's defended central bishop reaches at least two squares in the enemy half.
Central bishop d4 is defended.
Support Direct defenders: d1 and c3.
Targets Attacked squares: c5, e5, b6, f6, a7 and g7.
Home-rank king sealed and netted
+1.1
Black to move
1
2
3
4
5
6
7
8h
g
f
e
d
c
b
a
Black can play Qe1+, leaving the checked king no king move and at most three legal replies.
Move Qe1+: e3 to e1.
Targets Enemy pieces attacked after the move.
Checked king The move also checks the king on g1.
Masked slider battery aimed at the enemy king
+1.1
Black to move
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8h
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a
A friendly screen hides Black's line of attack.
Rear attacker Black's queen on c6.
Friendly screen d5 is the only piece blocking the line.
X-ray target The line points at White's king on g2.
Enemy piece defended only by king
+1.1
White to move
8
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Black's king alone defends the highlighted attacked material.
Attacked pieces e7 depends only on the king for defence.
Sole defender The king is their only defender.
Attackers c7 applies the pressure.
Safe minor-piece double attack
+1.1
White to move
8
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White can play Ng6, attacking 2 targets at once.
Move White can play Ng6: e5 to g6.
Targets The pieces attacked after the move.
Safe double attack available in one move
+1.1
White to move
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White's bishop on c5 can move to e7, attacking 3 valuable targets at once.
Forking move c5 and e7.
Simultaneous targets h4, d8, and f8.
Safe invader entrenched on the enemy pawn rank
+1.1
Black to move
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8h
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a
Black can play Rb2, which creates new threats.
Move Rb2: b8 to b2.
Targets Enemy pieces attacked after the move.
Safe advanced passed pawn poised to promote
+1.1
Black to move
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8h
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Black's passed pawn has an empty square ahead. Both squares have at least as many defenders as attackers.
Advanced pawn The pawn on c4 is on its 5th rank.
Support These friendly pieces defend the advanced pawn.
Clear next square The passer's next square is empty and not over-attacked.
Loaded queen battery aimed down the line at the enemy camp
+1.0
Black to move
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8h
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b
a
Black's queen stands behind a friendly screen, with the enemy queen farther down the same line.
Rear slider The queen on e7 points down the line.
Screen The piece on e4 stands between the slider and its target.
Target behind the screen The queen on e3 lies on the same line.

Material or mobility advantage

Material advantage for the side to move

Compact pawn mass against a splintered enemy skeleton

Bankable extra material with enemy counterplay muted

Healthy wing pawn majority

Positional dominance without material deficit

Two-file pawn bridgehead wedge or cohesive wall vs stranded pawn

Legal-move freedom surplus over a cramped opponent

Rook or queen on a line with no enemy pieces

Central-square control edge with material balance

Own king snug in an unpressured shelter

Connected frontmost pawns

Working queen versus benched enemy queen

Six-sector positional scoreboard edge

Live pawn levers versus a frozen enemy core

Broad quiet dominance scoreboard

Long-range firepower dominance

Quiet move threatens loose piece

Permanent holes in the enemy camp

One-way contact dominance over an untouched army

Rook development surplus over sleeping enemy rooks

Enemy pieces sharing a file

Rank-connected heavy piece coordination edge

Pawn storm race lead on the enemy king

Queenless king centralization edge

File-by-file pawn advance lead

One-way siege of unsupportable enemy pawns

More undefended enemy pieces than our own

Centralised army versus a scattered enemy force

Overall piece mobility edge

Crippled enemy minors versus a spotless own minor set

One-sided development tempo: enemy minors still stuck at home

One-way projected heavy batteries and open-file monopoly

Superior pawn structure and passed pawn edge

Unopposed active bishop ruling a vacant colour complex

Unopposed king-approach piece

Worst-piece breathing-room mismatch

Banked exchange or piece bounty

King breathing room mismatch

Unsupported advanced pawn attack

Our pieces stand where they cannot be kicked

Enemy king stranded without shelter

Caged enemy rooks versus our deep-breaching rook

Exclusive bishop pair with no material deficit

Slider fire on the breached enemy king shield

Cashable pawn: on-the-spot pawn grab that survives the exchange sequence

One-sided artillery barrage on the enemy king zone

Attacking force massed close to the enemy king

Slider x-ray pressure through an enemy screen onto a heavier piece

Forcing-stroke initiative surplus

Two distant entries into a weakened enemy camp

Protected pawn leading the advance

Safe piece infiltration in enemy territory

Pawn-space edge in opponent half

Safe fresh-threat move surplus over a silenced opponent

Enemy army bottled behind the midline under our bridgehead

Pawn-anchored minor entrenched on a permanent deep outpost

Rooks and queens with no friendly pawn ahead

Space-gaining pawn wedge in the centre

Existing double attack by one piece

Opponent starved of forcing resources

Queen net

Clamped enemy queen under one-way pressure

Stranded enemy king or safe double strike

Passed pawn majority edge

Opponent lags in mobilization and king shelter

Pressure on weak squares around the enemy king

Slider battery reinforced and trained on the enemy king

Heavy-piece pressure on the enemy pawn rank

Free bishop against pawn-strangled enemy bishop

Discovery-fork-initiative

Pending safe knight fork on the enemy heavy pieces

Ripe undefended enemy target capturable right now

Dormant enemy rooks parked on origin squares

Heavy piece raiding the enemy second rank

Pressure on the opponent weak pawns

Uncontested semi-open rook file

Central pawn wedge lead

Two-wing pawn superiority

Opponent saddled with a bad minor piece