Attack on the uncastled king: rook to a8 (a7·2)
c9-17849naming 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 e1, queen h1, rook g1 a7, bishop f2 h3, knight e2 c5, pawn c2 h2 b4 e4 g4 g5.
Black: king c8, queen h8, rook a8 g8, bishop c4 d6, knight b6 d8, pawn b5 e5 c6 f6 h7.
14 white and 13 black pieces are on the board; the puzzle position arises after move 19.
The position in numbers
White are ahead by 1 points of material (37 against 36; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on e1, the black king on c8.
It is White to move on move 19, with 43 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 5. Files fully open (no pawns of either colour): a, d — natural highways for the rooks and queen. Half-open for White: f.
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
19. Rxa8+ Nxa8 20. gxf6 Bxc5 21. g5+ Kb7 22. Bxc5
Why it works
- Brilliant! The rook on a8 is a sacrifice that works — you stand better (+2.9).
- Spot on — pawn to f6 (+2.8).
- Precise: pawn to g5 is the top choice (+3.0).
- Best move. bishop to c5 is exactly what the engine plays (+3.2).
- You reach a winning position (+3.2).
- If instead Nxa8, then gxf6 and you stay on top.
Move by move
- 19. Rxa8+ — rook to a8 (capture) with check
- Nxa8 — knight to a8 (capture)
- 20. gxf6 — pawn to f6 (capture)
- Bxc5 — bishop to c5 (capture)
- 21. g5+ — pawn to g5 with check
- Kb7 — king to b7
- 22. Bxc5 — bishop to c5 (capture)
Types in this puzzle
Discovered check
The moving piece opens a check — and is free to grab anything meanwhile.
With a discovered check the moving piece unmasks a check from the piece standing behind it. While the king deals with the check, the piece that moved grabs whatever it likes, free of charge. Look for your long-range piece on a line with the enemy king, with exactly one of your own pieces in between. The rule: among all the ways to step aside, pick the one that captures or attacks the most expensive loot.
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.
Zwischenzug
Before the obvious recapture — an in-between move that wins more.
A zwischenzug means refusing the obvious reply — usually a recapture — and playing a stronger move with tempo first. Typically it is a check or a deadly threat the opponent must answer, after which you calmly take what was hanging anyway. The sign: inside a sequence of exchanges you own a check or a threat that will not run away. Whenever a line looks forced, ask what poison you can slip in between the moves.
About this position
These pieces come from starting position #282.
SP-282 · BastionScout — King off-centre on c or f with a knight starting on the rim (a/h).
The king starts on c1, the rooks on b1 and g1, the queen on h1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
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: a2.
The setup belongs to the BastionScout family; read right to left it becomes position 581.
The engine's main line opens with Nb3, bringing the knight out to b3.
Morozov Balance Index: 31 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +32 centipawns for White (depth 43, 400 000 000 nodes).
Explore position #282Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-282
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