Attack on the uncastled king: bishop to a6 (e2·7)
sf-u-0074naming tag (square·N)The tactical motive
Uncastled king: the enemy king is stuck in the centre — punish it before it castles.
Mate in 3: a forced sequence that ends in checkmate.
Chess960 twist: use the unusual starting setup of the pieces.
Difficulty 1630 ShuffleRating — for advanced tacticians.
White to move — find the best continuation
Position on the board
White: king b2, queen d4, rook b1, bishop e2, knight g3, pawn a2 c2 d2 h2 b3 d6.
Black: king c8, rook b8, bishop a8, knight h6, pawn b6 c6 e6 a7 d7 h7.
11 white and 10 black pieces are on the board; the puzzle position arises after move 18.
Solution & explanation
Main line
18. Ba6+ Rb7 19. Qh8+ Ng8 20. Qxg8#
Why it works
- Great move! bishop to a6 keeps the pressure (#2).
- Spot on — queen to h8 (#1).
- Precise: queen to g8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Rb7, then Qh8+ and you stay on top.
Types in this puzzle
Mate in 3
A forced checkmate in three moves.
Mate in three is a forced staircase: each of your moves narrows the opponent's choices, and the third one ends the game. Look for the start among checks and sacrifices — quiet first moves are rare in mating problems, but deliciously sneaky. Keep the tree in your head: every defense gets its own branch. Do not stop calculating after move two — see the final mating picture with your own eyes.
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.
Provenance
Mined from the project's engine self-play games.
Verified by Stockfish at depth 20+.
Solution forcedness confirmed (verified).
Pack 013
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