Winning blow: queen to b7 (a8·4)
c9-20741naming 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 1200 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 a8, rook h1, bishop g1 e2, knight d3, pawn d2 g2 h2 b4.
Black: king d7, queen a2, rook h8, bishop g8, knight c2 c6, pawn h5 a6 b6 d6 b7 e7 g7.
10 white and 13 black pieces are on the board; the puzzle position arises after move 18.
The position in numbers
Black are ahead by 3 points of material (27 against 30; 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 d7.
It is White to move on move 18, with 31 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 7. Files fully open (no pawns of either colour): c, f — natural highways for the rooks and queen. Half-open for White: a, e.
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
18. Qxb7+ Ke6 19. Qxc6 Nxb4 20. Qc8+ Kf7 21. Nxb4
Why it works
- Great move! queen to b7 keeps the pressure (+4.6).
- Spot on — queen to c6 (+4.0).
- Precise: queen to c8 is the top choice (+4.5).
- Best move. knight to b4 is exactly what the engine plays (+4.3).
- You win a piece — the knight.
- If instead Ke6, then Qxc6 and you win the knight.
Move by move
- 18. Qxb7+ — queen to b7 (capture) with check
- Ke6 — king to e6
- 19. Qxc6 — queen to c6 (capture)
- Nxb4 — knight to b4 (capture)
- 20. Qc8+ — queen to c8 with check
- Kf7 — king to f7
- 21. Nxb4 — knight to b4 (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.
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.
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 #462.
SP-462 · ThroneGuard — King on a central file (d/e) with both knights on inner files — the classic-type setup.
The king starts on d1, the rooks on a1 and h1, the queen on e1.
Castling ends where it always does: king to g1 and rook to f1 on the short side, king to c1 and rook to d1 on the long one.
The bishops stand on f1 and g1; their long diagonals reach a6 and a7 once the e- and f-pawns step aside.
One second-rank pawn starts with no defender at all: b2.
The setup belongs to the ThroneGuard family; read right to left it becomes position 692.
The engine's main line opens with f4.
Morozov Balance Index: 91 of 100 — class A — most balanced. Engine evaluation of the starting position: +13 centipawns for White (depth 48, 400 000 000 nodes).
Explore position #462Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-462
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