Winning blow: knight to d5 (c3·10)
c9-24739naming 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 d2, rook f1 a3, knight c3, pawn a2 c2 d3 g4 h5.
Black: king e7, rook b4 h6, knight e5 d6, pawn d5 c7 d7.
9 white and 8 black pieces are on the board; the puzzle position arises after move 36.
The position in numbers
Black are ahead by 1 points of material (18 against 19; 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 e7.
It is White to move on move 36, with 34 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 3. Files fully open (no pawns of either colour): b, e, f — natural highways for the rooks and queen.
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
36. Nxd5+ Ke6 37. Nxc7+ Ke7 38. Nd5+ Ke6 39. Nxb4
Why it works
- Great move! knight to d5 keeps the pressure (+5.6).
- Spot on — knight to c7 (+5.7).
- Strong! knight to d5 is the sharp choice (+5.6).
- Best move. knight to b4 is exactly what the engine plays (+5.7).
- You win a piece — the rook.
- If instead Ke6, then Nxc7+ and you stay on top.
Move by move
- 36. Nxd5+ — knight to d5 (capture) with check
- Ke6 — king to e6
- 37. Nxc7+ — knight to c7 (capture) with check
- Ke7 — king to e7
- 38. Nd5+ — knight to d5 with check
- Ke6 — king to e6
- 39. 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.
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 #531.
SP-531 · ThroneGuard — Both knights start on inner files (b–g) while the king sits centrally on d or e — one of 204 positions filed here.
The king starts on d1, the rooks on b1 and g1, 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.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
The pawn on c2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the ThroneGuard family; read right to left it becomes position 515.
The engine's main line opens with b3.
Morozov Balance Index: 81 of 100 — class A — most balanced. Engine evaluation of the starting position: +13 centipawns for White (depth 47, 400 000 000 nodes).
In 50 self-play games White scored 54.0% (95% CI 40.4–67.0%).
Explore position #531Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-531
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