Winning blow: queen to a6 (d3·3)
c9-14678naming 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.
A fork made possible by the Chess960 piece placement.
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.
A set-up fork needs one preparing move before the fork lands — a check that drives the king onto the forking square, or a capture that lines the targets up. Find the preparation first, then the fork it makes possible.
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 c1, queen d3, rook d1 b3, pawn c2 g3 a4 e4 f4 h4.
Black: king a8, queen f2, rook c7 c8, bishop g6, pawn g4 a5 b6 e6 f6.
10 white and 10 black pieces are on the board; the puzzle position arises after move 30.
The position in numbers
Black are ahead by 2 points of material (25 against 27; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c1, the black king on a8.
It is White to move on move 30, with 33 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): d — natural highways for the rooks and queen. Half-open for White: b.
The White king has 2 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
30. Qa6+ Kb8 31. Rxb6+ Qxb6 32. Qxb6+
Why it works
- Great move! queen to a6 keeps the pressure (+4.6).
- Well found: rook to b6 (+4.8).
- Strong! queen to b6 is the sharp choice (+4.9).
- You win a piece — the queen.
- If instead Kb8, then Rxb6+ and you stay on top.
Move by move
- 30. Qa6+ — queen to a6 with check
- Kb8 — king to b8
- 31. Rxb6+ — rook to b6 (capture) with check
- Qxb6 — queen to b6 (capture)
- 32. Qxb6+ — queen to b6 (capture) with check
Types in this puzzle
Setup fork
The random setup allows a fork that classical chess never sees.
A setup fork is a double attack that exists only because of the unusual starting squares — in classical chess these targets never stand side by side. Look for pairs of undefended pieces on your opponent's back rank and for squares from which a knight or pawn hits both at once. Such forks usually appear within the first moves, before the pieces disperse. In every new position, note right away which starting pieces are defended by no one.
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.
Win the pinned piece
The pinned piece cannot run — attack it again and win it.
A pinned piece cannot flee, which means you can win it outright by attacking it one more time. Count attackers against defenders: if you outnumber them, the piece is yours. The best extra attacker is a pawn, since it costs less than anything it might capture. Do not rush the capture — build up the pressure first, then harvest.
About this position
These pieces come from starting position #681.
SP-681 · 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 h1, the queen on a1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
The bishops stand on d1 and e1; their long diagonals reach h5 and a5 once the e- and d-pawns step aside.
One second-rank pawn starts with no defender at all: g2.
The setup belongs to the BastionGuard family; read right to left it becomes position 473.
The engine's main line opens with b4.
Morozov Balance Index: 10 of 100 — class D — largest edge. Engine evaluation of the starting position: +43 centipawns for White (depth 42, 400 000 000 nodes).
Explore position #681Provenance
Mined from the project's engine self-play games.
Pack 006 · SP-681
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