Winning blow: rook to a7 (a8)
c9-12710naming 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.
Winning tactic: there is a move that gains a decisive advantage — find it.
Difficulty 1060 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.
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 c2, queen e5, rook a8, bishop g1 d5, pawn b3 h3 c6.
Black: king c7, queen d6, rook d8, knight f8, pawn g3 f5 g6 e7 h7.
8 white and 9 black pieces are on the board; the puzzle position arises after move 28.
The position in numbers
White are ahead by 1 points of material (23 against 22; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c2, the black king on c7.
It is White to move on move 28, with 51 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 3 pawns, Black 5. Files fully open (no pawns of either colour): a, d — natural highways for the rooks and queen. Half-open for White: e, f, g.
White hold the bishop pair, an edge in open lines. The White king has 7 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
28. Ra7+ Kb8 29. c7+ Kc8 30. cxd8=R+
Why it works
- Great move! rook to a7 keeps the pressure (#5).
- Spot on — pawn to c7 (#5).
- Precise: pawn to d8 is the top choice (#4).
- You win a piece — the rook.
- If instead Kb8, then c7+ and you stay on top.
Move by move
- 28. Ra7+ — rook to a7 with check
- Kb8 — king to b8
- 29. c7+ — pawn to c7 with check
- Kc8 — king to c8
- 30. cxd8=R+ — pawn to d8 (capture) with check
Types in this puzzle
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.
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.
Underpromotion
Promoting to a knight or rook — not a queen — is the only way to win.
Underpromotion means choosing a knight, rook or bishop instead of a queen — and winning precisely because of it. The usual hero is the knight, which delivers a check or a fork from the promotion square in a way no queen can. A rook is chosen when a fresh queen would produce stalemate. When your pawn reaches the last rank, never promote on autopilot — first ask what the knight can do.
About this position
These pieces come from starting position #783.
SP-783 · BastionGuard — King shifted to c or f, knights kept clear of the edges — 168 positions in all.
The king starts on c1, the rooks on b1 and e1, the queen on a1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
The pawn on c2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the BastionGuard family; read right to left it becomes position 176.
The engine's main line opens with b4.
Morozov Balance Index: 6 of 100 — class D — largest edge. Engine evaluation of the starting position: +48 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #783Provenance
Mined from the project's engine self-play games.
Pack 006 · SP-783
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