Winning blow: rook to a8 (a1·9)
c9-09506naming 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 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.
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 d1, rook a1 e1, bishop e3 h5, pawn c2 h2 d3 g3 e4 f4.
Black: king c8, rook a8 f8, bishop d7 e7, knight c4 g6, pawn e5 d6 f6 c7 g7 h7.
11 white and 13 black pieces are on the board; the puzzle position arises after move 25.
The position in numbers
Black are ahead by 6 points of material (22 against 28; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on d1, the black king on c8.
It is White to move on move 25, with 36 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): a, b — 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
25. Rxa8+ Kb7 26. Ra7+ Kc6 27. dxc4 exf4 28. gxf4
Why it works
- Great move! rook to a8 keeps the pressure (+2.7).
- Well found: rook to a7 (+3.0).
- Strong! pawn to c4 is the sharp choice (+3.6).
- Best move. pawn to f4 is exactly what the engine plays (+3.7).
- You win a piece — the rook.
- If instead Kb7, then Ra7+ and you win the rook.
Move by move
- 25. Rxa8+ — rook to a8 (capture) with check
- Kb7 — king to b7
- 26. Ra7+ — rook to a7 with check
- Kc6 — king to c6
- 27. dxc4 — pawn to c4 (capture)
- exf4 — pawn to f4 (capture)
- 28. gxf4 — pawn to f4 (capture)
Types in this puzzle
Winning blow
Find the strike that wins material by force.
A winning blow is a forced material gain that does not fit a single textbook motif. The general tactical recipe applies: spot loose pieces, an awkwardly placed king, overloaded lines. Go through the forcing moves in order of violence — checks, captures, threats — because most combinations start with one of them. Do not judge by feel: calculate the concrete line until the outcome is beyond doubt.
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.
About this position
These pieces come from starting position #870.
SP-870 · ThroneScout — King on a central file (d/e) with a knight starting on the rim (a/h).
The king starts on d1, the rooks on b1 and e1, the queen on a1.
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.
The bishops stand on c1 and f1; their long diagonals reach h6 and a6 once the d- and e-pawns step aside.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the ThroneScout family; read right to left it becomes position 86.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 10 of 100 — class D — largest edge. Engine evaluation of the starting position: +44 centipawns for White (depth 45, 400 000 000 nodes).
In 50 self-play games White scored 55.0% (95% CI 41.3–67.9%).
Explore position #870Provenance
Mined from the project's engine self-play games.
Pack 007 · SP-870
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