Attack on the uncastled king: bishop to g7 (a1·13)
c9-24793naming 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.
A fork made possible by the Chess960 piece placement.
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 1650 ShuffleRating — for advanced tacticians.
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.
A set-up fork needs one preparing move before the fork lands — a check that drives the king onto the forking square, or a capture that lines the targets up. Find the preparation first, then the fork it makes possible.
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 g1, queen g3, rook c1 f1, bishop a1 d1, knight e2 g5, pawn a2 d2 g2 h2 b3 c4 e4 f4.
Black: king f8, queen e7, rook h6 c8, bishop a8 d8, knight c6 g8, pawn c5 h5 b6 e6 a7 d7 f7 g7.
16 white and 16 black pieces are on the board; the puzzle position arises after move 11.
The position in numbers
Material is level — 39 points of pieces on each side (pawn = 1, knight and bishop = 3, rook = 5, queen = 9).
The white king stands on g1, the black king on f8.
It is White to move on move 11, with 40 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 8 pawns, Black 8. No file is fully open, so the heavy pieces have to be pried in.
The White king has 2 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
11. Bxg7+ Ke8 12. Bxh6
Why it works
- Great move! bishop to g7 keeps the pressure (+4.0).
- Spot on — bishop to h6 (+4.8).
- You win a piece — the rook.
- If instead Ke8, then Bxh6 and you win the rook.
Move by move
- 11. Bxg7+ — bishop to g7 (capture) with check
- Ke8 — king to e8
- 12. Bxh6 — bishop to h6 (capture)
Types in this puzzle
Setup fork
The random setup allows a fork that classical chess never sees.
A setup fork is a double attack that exists only because of the unusual starting squares — in classical chess these targets never stand side by side. Look for pairs of undefended pieces on your opponent's back rank and for squares from which a knight or pawn hits both at once. Such forks usually appear within the first moves, before the pieces disperse. In every new position, note right away which starting pieces are defended by no one.
Royal fork
A fork with check: the king must move, and the second piece is lost.
A royal fork is a fork with check — one of the two targets is the king itself. The check must be answered first, so nobody is left to rescue the second piece. Look for squares where your piece gives check and simultaneously attacks an undefended queen or rook. It is the most reliable fork of all, because your opponent literally has no choice.
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 #225.
SP-225 · BastionGuard — King shifted to c or f, knights kept clear of the edges — 168 positions in all.
The king starts on f1, the rooks on c1 and h1, the queen on e1.
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.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
One second-rank pawn starts with no defender at all: a2.
The setup belongs to the BastionGuard family; read right to left it becomes position 635.
The engine's main line opens with b4.
Morozov Balance Index: 80 of 100 — class A — most balanced. Engine evaluation of the starting position: +17 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #225Provenance
Mined from the project's engine self-play games.
Pack 013 · SP-225
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