Attack on the uncastled king: bishop to d7 (a4·7)
c9-10232naming tag (square·N)Opens in the app if installed, otherwise downloads the APK.
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 1200 ShuffleRating — club-player level.
White to move — find the best continuation
How to recognize this tactic
In Chess960 the pieces start on unfamiliar squares, so tactics appear earlier and from unusual angles. Do not trust classical patterns — read the actual lines of the bishops, the rooks and the queen from where they really stand in this position.
An uncastled king in the centre is a standing target. Look for ways to open the central files and diagonals against it with checks and threats before it can shelter — every tempo the king spends in the middle is a chance for a combination.
This position hides a concrete tactic that wins material or mates. Start with the most forcing candidate moves — checks, captures and threats — and calculate each to a clear end before choosing; the winning line is usually the one the opponent cannot meet.
General method: before you move, list the forcing candidates — every check, every capture, every direct threat — and calculate those first. The solution to a tactic is almost always among them.
Position on the board
White: king f1, queen d3, rook c1 h1, bishop e1 a4, knight c3, pawn a2 b2 d2 e2 g2 f3 c4 h4.
Black: king f8, queen b6, rook h7 c8, bishop d7 d8, knight f6 c7, pawn a5 c5 e5 d6 b7 f7 g7.
15 white and 15 black pieces are on the board; the puzzle position arises after move 13.
The position in numbers
Black are ahead by 2 points of material (36 against 38; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on f1, the black king on f8.
It is White to move on move 13, with 42 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 8 pawns, Black 7. No file is fully open, so the heavy pieces have to be pried in.
The White king has 3 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
13. Bxd7 e4 14. Nxe4 Nxd7 15. Nxd6 Ne5 16. Qxh7
Why it works
- Brilliant! The bishop on d7 is a sacrifice that works — you are winning (+3.0).
- Well found: knight to e4 (+2.7).
- Strong! knight to d6 is the sharp choice (+2.9).
- Best move. queen to h7 is exactly what the engine plays (+3.0).
- You win a piece — the rook.
- If instead e4, then Nxe4 and you win the bishop.
Move by move
- 13. Bxd7 — bishop to d7 (capture)
- e4 — pawn to e4
- 14. Nxe4 — knight to e4 (capture)
- Nxd7 — knight to d7 (capture)
- 15. Nxd6 — knight to d6 (capture)
- Ne5 — knight to e5
- 16. Qxh7 — queen to h7 (capture)
Types in this puzzle
Discovered attack
A piece steps aside and opens a second attack from the piece behind it.
A discovered attack works like a curtain: one piece steps off the line and unveils the long-range piece behind it. The beauty is that the moving piece can create a second threat of its own — two attacks in one move. Look for your stacked pairs: a bishop or rook behind a knight or pawn, aimed through them at something valuable. Send the front piece to the most aggressive square — a discovery without a second threat wastes half its power.
Only move
Everything else loses — find the only move that holds.
An only move is a position where everything loses except one single continuation. You cannot play "by hand" here: run through fundamentally different defenses — run away, block, trade, counterattack — and discard the ones that fail. The hallmark of these puzzles is that the obvious moves lose quickly while the solution often looks strange. First understand exactly what the threat is — then the one saving move reveals itself.
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.
About this position
These pieces come from starting position #217.
SP-217 · BastionScout — A c- or f-file king with at least one knight out on the edge.
The king starts on f1, the rooks on c1 and h1, the queen on b1.
Castling ends where it always does: king to g1 and rook to f1 on the short side, king to c1 and rook to d1 on the long one.
The bishops stand on d1 and e1; their long diagonals reach h5 and a5 once the e- and d-pawns step aside.
The pawn on g2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the BastionScout family; read right to left it becomes position 649.
The engine's main line opens with b4.
Morozov Balance Index: 100 of 100 — class A — most balanced. Engine evaluation of the starting position: +3 centipawns for White (depth 47, 400 000 000 nodes).
In 50 self-play games White scored 50.0% (95% CI 36.6–63.4%).
Explore position #217Provenance
Mined from the project's engine self-play games.
Pack 007 · SP-217
Similar puzzles
In your browser or in the Android app. Nothing to install · Free, no ads