Winning blow: rook to a6 (c6)
c9-23126naming 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 1430 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 b1, queen f8, rook c6, bishop f1, pawn a2 b2 h3 c4 d5.
Black: king a7, queen d4, rook d7 a8, pawn f2 b4 g6.
9 white and 7 black pieces are on the board; the puzzle position arises after move 39.
The position in numbers
Material is level — 22 points of pieces on each side (pawn = 1, knight and bishop = 3, rook = 5, queen = 9).
The white king stands on b1, the black king on a7.
It is White to move on move 39, with 40 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 3. Files fully open (no pawns of either colour): e — natural highways for the rooks and queen. Half-open for White: f, g.
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
39. Ra6+ Kxa6 40. Qxa8+ Kb6 41. Qc6+ Ka7 42. Qxd7+
Why it works
- Great move! rook to a6 keeps the pressure (+6.0).
- Well found: queen to a8 (+6.5).
- Strong! queen to c6 is the sharp choice (+7.5).
- Great move! queen to d7 keeps the pressure (+7.8).
- You win a piece — the rook.
- If instead Kxa6, then Qxa8+ and you stay on top.
Move by move
- 39. Ra6+ — rook to a6 with check
- Kxa6 — king to a6 (capture)
- 40. Qxa8+ — queen to a8 (capture) with check
- Kb6 — king to b6
- 41. Qc6+ — queen to c6 with check
- Ka7 — king to a7
- 42. Qxd7+ — queen to d7 (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.
Mate defense
Mate is threatened — parry it and stay on top.
Mate defense: your opponent is one move from mating you — but it is your turn, and that changes everything. Find the defense that kills the mating threat while keeping your advantage: often a check or a counter-threat that leaves no time for the mate. First name the exact square where the mate would land — otherwise you are defending blind. The mistake is playing a "defensive" move that does not actually remove the threat.
Skewer
A line attack forces the valuable piece to move, exposing the one behind it.
A skewer is a pin turned inside out: the valuable piece stands in front and something cheaper hides behind it. The big piece must step aside, and you collect the one that was sheltering in its shadow. Scan for the enemy king or queen sharing a file, rank or diagonal with another enemy piece. The deadliest version comes with check — the king moves, the rook behind it dies.
About this position
These pieces come from starting position #794.
SP-794 · BastionScout — The king starts one file off-centre, on c or f, and a knight begins in a corner.
The king starts on c1, the rooks on a1 and g1, the queen on b1.
The king already stands on c1, so castling long moves only the rook, from a1 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: h2.
The setup belongs to the BastionScout family; read right to left it becomes position 165.
The engine's main line opens with e3.
Morozov Balance Index: 0 of 100 — class D — largest edge. Engine evaluation of the starting position: +67 centipawns for White (depth 44, 400 000 000 nodes).
In 50 self-play games White scored 62.0% (95% CI 48.2–74.1%).
Explore position #794Provenance
Mined from the project's engine self-play games.
Pack 011 · SP-794
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