Winning blow: queen to b7 (b3·2)
c9-20994naming 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 1010 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 d1, queen b3, rook c1 d3, bishop e1 c6, knight e5, pawn a2 d2 e2 g2 f4 h4.
Black: king c8, queen d6, rook e8, bishop c7, knight e4, pawn f5 e6 g6 h6.
13 white and 9 black pieces are on the board; the puzzle position arises after move 25.
The position in numbers
White are ahead by 10 points of material (34 against 24; 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 51 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 4. Files fully open (no pawns of either colour): b, c — natural highways for the rooks and queen.
White hold the bishop pair, an edge in open lines. The White king has 1 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
25. Qb7+ Kd8 26. Qa8+ Bb8 27. Qxb8+
Why it works
- Best move. queen to b7 is exactly what the engine plays (#4).
- Spot on — queen to a8 (#3).
- Precise: queen to b8 is the top choice (#2).
- You win a piece — the bishop.
- If instead Kd8, then Qa8+ and you stay on top.
Move by move
- 25. Qb7+ — queen to b7 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.
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.
About this position
These pieces come from starting position #377.
SP-377 · BastionScout — King shifted to c or f, with a knight committed to the corner from move one.
The king starts on c1, the rooks on b1 and f1, the queen on h1.
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: a2.
The setup belongs to the BastionScout family; read right to left it becomes position 297.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 37 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +30 centipawns for White (depth 43, 400 000 000 nodes).
Explore position #377Provenance
Mined from the project's engine self-play games.
Pack 006 · SP-377
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