Winning blow: queen to c6 (b7·3)
c9-20405naming 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 g1, queen b7, rook d1 a2, bishop b6, pawn b2 c2 g2 h2 f3 a5.
Black: king d8, queen f8, rook c8 h8, bishop c6 c7, knight d5, pawn h3 f7 g7.
11 white and 10 black pieces are on the board; the puzzle position arises after move 23.
The position in numbers
Black are ahead by 3 points of material (28 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 g1, the black king on d8.
It is White to move on move 23, with 37 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 3. Files fully open (no pawns of either colour): d, e — natural highways for the rooks and queen.
Black hold the bishop pair, an edge in open lines. 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
23. Qxc6 Bxb6+ 24. Qxb6+ Ke7 25. Rxd5
Why it works
- Great move! queen to c6 keeps the pressure (+5.7).
- Well found: queen to b6 (+6.3).
- Strong! rook to d5 is the sharp choice (+6.4).
- You win a piece — the bishop.
- If instead Bxb6+, then Qxb6+ and you win the bishop.
Move by move
- 23. Qxc6 — queen to c6 (capture)
- Bxb6+ — bishop to b6 (capture) with check
- 24. Qxb6+ — queen to b6 (capture) with check
- Ke7 — king to e7
- 25. Rxd5 — rook to d5 (capture)
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.
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.
Remove the defender
Capture the guard first — then take what it protected.
Removing the defender is the straightforward plan: capture the guard first, then take what it guarded. Unlike deflection, the defender is not lured away — it is traded off or destroyed on the spot. Stare at the target you crave and ask who defends it, and whether that defender can be profitably eaten. Count the whole capture sequence, not just the first move — the trade must pay off at the end.
About this position
These pieces come from starting position #728.
SP-728 · BastionGuard — A c- or f-file king and two knights on inner files (b–g).
The king starts on c1, the rooks on a1 and h1, the queen on f1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
The bishops stand on b1 and e1; their long diagonals reach h7 and a5 once the c- and d-pawns step aside.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the BastionGuard family; read right to left it becomes position 429.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 61 of 100 — class B — balanced. Engine evaluation of the starting position: +23 centipawns for White (depth 43, 400 000 000 nodes).
Explore position #728Provenance
Mined from the project's engine self-play games.
Pack 006 · SP-728
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