Attack on the uncastled king: bishop to d7 (g4·5)
c9-27718naming 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 1290 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 b1, rook a1 g8, bishop c1 g4, pawn b2 c2 d2 g2 h2 a3.
Black: king b8, rook g1 a8, bishop f6 c8, pawn a4 g6 b7 c7 d7 h7.
11 white and 11 black pieces are on the board; the puzzle position arises after move 13.
The position in numbers
Material is level — 22 points of pieces on each side (pawn = 1, knight and bishop = 3, rook = 5, queen = 9).
The white king stands on b1, the black king on b8.
It is White to move on move 13, with 26 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 6. Files fully open (no pawns of either colour): e, f — natural highways for the rooks and queen.
The White king has 1 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
13. Bxd7 Ka7 14. Rxc8 Rxc8 15. Bxc8
Why it works
- Brilliant! The bishop on d7 is a sacrifice that works — you stand better (+3.0).
- Spot on — rook to c8 (+3.0).
- Strong! bishop to c8 is the sharp choice (+2.8).
- You win a piece — the rook.
- If instead Ka7, then Rxc8 and you win the bishop.
Move by move
- 13. Bxd7 — bishop to d7 (capture)
- Ka7 — king to a7
- 14. Rxc8 — rook to c8 (capture)
- Rxc8 — rook to c8 (capture)
- 15. Bxc8 — bishop to c8 (capture)
Types in this puzzle
Absolute pin
A piece is pinned against its king — it cannot legally move.
An absolute pin freezes a piece on the line between its own king and your long-range attacker: moving it is simply illegal. The pattern is three units on one straight line — your bishop, rook or queen, an enemy piece, and the enemy king behind it. A pinned piece neither attacks nor defends anything: treat it as if it were off the board. Pile up on it, ideally with a pawn, because running away is against the rules.
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.
Trapped piece
The attacked piece has no safe square — it is caught.
Trapping a piece means the attacked piece has no safe square left — it simply perishes. Do not chase it around; build a cage instead: cut off the escape squares with pawns and pieces first, and attack last. The typical victim has wandered deep into your camp or is stuck at the edge of the board, where its mobility is tiny. And always check the way home for your own raiders — or the trapped piece will be yours.
About this position
These pieces come from starting position #917.
SP-917 · RampartScout — King on b or g with a knight already on the edge — the least common of the position families (72 in all).
The king starts on b1, the rooks on a1 and e1, the queen on f1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
The bishops stand on c1 and d1; their long diagonals reach h6 and h5 once the d- and e-pawns step aside.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the RampartScout family; read right to left it becomes position 42.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 28 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +33 centipawns for White (depth 48, 400 000 000 nodes).
Explore position #917Provenance
Mined from the project's engine self-play games.
Pack 009 · SP-917
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