Winning blow: pawn to b5 (b4·6)
c9-13081naming 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 1560 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 d2, queen d3, rook e1, knight f4, pawn c2 f2 h2 g3 b4.
Black: king c6, queen a6, bishop h8, knight f6 b8, pawn f5 h5 b6 g6 a7.
9 white and 10 black pieces are on the board; the puzzle position arises after move 22.
The position in numbers
Black are ahead by 1 points of material (22 against 23; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on d2, the black king on c6.
It is White to move on move 22, with 50 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 5. Files fully open (no pawns of either colour): d, e — natural highways for the rooks and queen. Half-open for White: a.
The White king has 5 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
22. b5+ Qxb5 23. Re6+ Kb7 24. Qxb5
Why it works
- Great move! pawn to b5 keeps the pressure (+8.0).
- Well found: rook to e6 (+8.1).
- Strong! queen to b5 is the sharp choice (+8.3).
- You win a piece — the queen.
- If instead Qxb5, then Re6+ and you stay on top.
Move by move
- 22. b5+ — pawn to b5 with check
- Qxb5 — queen to b5 (capture)
- 23. Re6+ — rook to e6 with check
- Kb7 — king to b7
- 24. Qxb5 — queen to b5 (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.
Zwischenzug
Before the obvious recapture — an in-between move that wins more.
A zwischenzug means refusing the obvious reply — usually a recapture — and playing a stronger move with tempo first. Typically it is a check or a deadly threat the opponent must answer, after which you calmly take what was hanging anyway. The sign: inside a sequence of exchanges you own a check or a threat that will not run away. Whenever a line looks forced, ask what poison you can slip in between the moves.
About this position
These pieces come from starting position #355.
SP-355 · ThroneGuard — A central king (d or e) and two knights tucked onto inner files: the family that holds the standard array, SP-518.
The king starts on d1, the rooks on c1 and e1, the queen on f1.
Castling long simply swaps the two pieces: the king on d1 and the rook on c1 trade places.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
The second rank carries 2 pawns with no defender at all: a2, h2.
The setup belongs to the ThroneGuard family; read right to left it becomes position 307.
The engine's main line opens with g4.
Morozov Balance Index: 65 of 100 — class B — balanced. Engine evaluation of the starting position: +22 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #355Provenance
Mined from the project's engine self-play games.
Pack 011 · SP-355
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