Attack on the uncastled king: rook to a6 (a3·2)
c9-09300naming 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 1390 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 g1, queen a1, rook h1 a3, bishop e1 e2, knight c1, pawn c2 f2 g2 e3 b4 d4 b5 h5.
Black: king g8, queen b6, rook h7 b8, bishop f7 f8, knight d6 b7, pawn d5 f5 g5 e6 h6 c7.
15 white and 14 black pieces are on the board; the puzzle position arises after move 16.
The position in numbers
Black are ahead by 1 points of material (36 against 37; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on g1, the black king on g8.
It is White to move on move 16, with 37 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 8 pawns, Black 6. Files fully open (no pawns of either colour): a — natural highways for the rooks and queen.
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
16. Ra6 Be8 17. g4 Rc8 18. gxf5 exf5 19. Rxb6
Why it works
- Great move! rook to a6 keeps the pressure (+2.6).
- pawn to g4 develops smoothly.
- Precise: pawn to f5 is the top choice (+2.7).
- Brilliant! The rook on b6 is a sacrifice that works — you stand better (+2.7).
- You win a piece — the queen.
- If instead Be8, then g4 and you stay on top.
Move by move
- 16. Ra6 — rook to a6
- Be8 — bishop to e8
- 17. g4 — pawn to g4
- Rc8 — rook to c8
- 18. gxf5 — pawn to f5 (capture)
- exf5 — pawn to f5 (capture)
- 19. Rxb6 — rook to b6 (capture)
Types in this puzzle
Queen trap
The strongest piece ventures too far — and cannot come back.
A queen trap catches the strongest piece after it ventures too far and finds no way home. The usual story is a queen grabbing a distant pawn — the classic poisoned pawn. The warning signs: the queen has few retreat squares, and enemy minor pieces cut them off one by one, gaining tempo with every move. Before your queen snacks on a pawn in enemy territory, count her escape routes — fewer than two means stay home.
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 #394.
SP-394 · RampartGuard — Both knights begin on inner files while the king sits on the wing (b/g); mirror twins stay together in this family.
The king starts on g1, the rooks on b1 and h1, the queen on a1.
The king already stands on its castled square, so castling short moves only the rook, from h1 to f1.
The bishops stand on e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
One second-rank pawn starts with no defender at all: c2.
The setup belongs to the RampartGuard family; read right to left it becomes position 757.
The engine's main line opens with c4.
Morozov Balance Index: 51 of 100 — class B — balanced. Engine evaluation of the starting position: +26 centipawns for White (depth 48, 400 000 000 nodes).
Explore position #394Provenance
Mined from the project's engine self-play games.
Pack 010 · SP-394
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