Attack on the uncastled king: pawn to c5 (c4·5)
c9-25601naming tag (square·N)The tactical motive
Chess960 twist: use the unusual starting setup of the pieces.
Uncastled king: the enemy king is stuck in the centre — punish it before it castles.
Winning tactic: there is a move that gains a decisive advantage — find it.
Difficulty 1250 ShuffleRating — club-player level.
White to move — find the best continuation
Position on the board
White: king d1, rook h1, bishop b1 a5, knight e2 b3, pawn a2 f2 g2 h2 c4.
Black: king d8, rook c8, bishop e8 h8, knight b6 g8, pawn f5 a7 b7 d7 e7 h7.
11 white and 12 black pieces are on the board; the puzzle position arises after move 12.
Solution & explanation
Main line
12. c5 e6 13. cxb6 axb6 14. Bxb6+
Why it works
- Great move! pawn to c5 keeps the pressure (+3.2).
- Spot on — pawn to b6 (+3.4).
- Precise: bishop to b6 is the top choice (+3.8).
- You win a piece — the knight.
- If instead e6, then cxb6 and you win the knight.
Types in this puzzle
Win the pinned piece
The pinned piece cannot run — attack it again and win it.
A pinned piece cannot flee, which means you can win it outright by attacking it one more time. Count attackers against defenders: if you outnumber them, the piece is yours. The best extra attacker is a pawn, since it costs less than anything it might capture. Do not rush the capture — build up the pressure first, then harvest.
Uncastled king
The king lingered in the middle — punish the delay.
Punishing the uncastled king: your opponent delayed castling, and now his king is stuck on its starting square under fire. In Chess960 this is deadlier than in classical chess — the king may start in the center or near the edge, and the familiar defensive setups simply do not apply. The signs: the victim still holds castling rights, and the files toward his king are half-open. Open lines before the king manages to hide.
Development punish
Half the army still asleep — the attack breaks through.
Punishing lazy development: half of your opponent's army is asleep on its starting squares, which means you outnumber him where the fight is. Count not the pieces on the board but the pieces in play — if five or more of his pieces have never moved, look for a forcing attack. The sign is a development lead plus open lines toward his king. Strike immediately: give him two quiet moves and the advantage evaporates.
About this position
These pieces come from starting position #248.
SP-248 · ThroneScout — The king starts on d or e while at least one knight begins in a corner.
The king starts on d1, the rooks on c1 and h1, the queen on f1.
Castling long simply swaps the two pieces: the king on d1 and the rook on c1 trade places.
The bishops stand on b1 and e1; their long diagonals reach h7 and a5 once the c- and d-pawns step aside.
One second-rank pawn starts with no defender at all: b2.
The setup belongs to the ThroneScout family; read right to left it becomes position 621.
The engine's main line opens with c4.
Morozov Balance Index: 31 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +32 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #248Provenance
Mined from the project's engine self-play games.
Pack 009 · SP-248
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