Winning blow: queen to b7 (a6·4)
c9-27325naming 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 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.
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 b1, queen a6, rook f1, bishop h2, knight e1 a5, pawn b2 c2 g2 d3.
Black: king c7, queen f7, rook g4 a8, bishop d6, knight c8, pawn e3 f4 h5 c6 a7 d7.
10 white and 12 black pieces are on the board; the puzzle position arises after move 22.
The position in numbers
Black are ahead by 4 points of material (27 against 31; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b1, the black king on c7.
It is White to move on move 22, with 28 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 6. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: a, e, f, h.
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
22. Qb7+ Kd8 23. Nxc6+ Ke8 24. Qxa8 dxc6 25. Qxc8+
Why it works
- Great move! queen to b7 keeps the pressure (+3.5).
- Well found: knight to c6 (+3.5).
- Strong! queen to a8 is the sharp choice (+3.4).
- Great move! queen to c8 keeps the pressure (+3.5).
- You win a piece — the rook.
- If instead Kd8, then Nxc6+ and you stay on top.
Move by move
- 22. Qb7+ — queen to b7 with check
- Kd8 — king to d8
- 23. Nxc6+ — knight to c6 (capture) with check
- Ke8 — king to e8
- 24. Qxa8 — queen to a8 (capture)
- dxc6 — pawn to c6 (capture)
- 25. Qxc8+ — queen to c8 (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.
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.
About this position
These pieces come from starting position #749.
SP-749 · RampartGuard — A wing king (b/g) with no knight on the a- or h-file.
The king starts on b1, the rooks on a1 and h1, the queen on f1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
The bishops stand on d1 and g1; their long diagonals reach h5 and a7 once the e- and f-pawns step aside.
One second-rank pawn starts with no defender at all: d2.
The setup belongs to the RampartGuard family; read right to left it becomes position 408.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 4 of 100 — class D — largest edge. Engine evaluation of the starting position: +50 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #749Provenance
Mined from the project's engine self-play games.
Pack 011 · SP-749
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