Winning blow: knight to c5 (b7·5)
c9-17161naming 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.
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.
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 c1, queen b4, rook a1 f1, bishop d3, knight g3 b7, pawn b2 h2 c3 f3 e4 a5 d5.
Black: king c8, queen e7, rook a8 f8, bishop h3 c5, knight g2 e3, pawn e5 a6 f6 c7 d7 g7 h7.
14 white and 15 black pieces are on the board; the puzzle position arises after move 17.
The position in numbers
Black are ahead by 3 points of material (35 against 38; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c1, the black king on c8.
It is White to move on move 17, with 36 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 7. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: g.
Black hold the bishop pair, an edge in open lines. The White king has 2 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
17. Nxc5 Qd6 18. Qb7+ Kd8 19. Qxa8+
Why it works
- Great move! knight to c5 keeps the pressure (+3.8).
- Spot on — queen to b7 (+3.9).
- Precise: queen to a8 is the top choice (+4.0).
- You win a piece — the rook.
- If instead Qd6, then Qb7+ and you win the bishop.
Move by move
- 17. Nxc5 — knight to c5 (capture)
- Qd6 — queen to d6
- 18. Qb7+ — queen to b7 with check
- Kd8 — king to d8
- 19. Qxa8+ — queen to a8 (capture) with check
Types in this puzzle
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.
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.
About this position
These pieces come from starting position #636.
SP-636 · ThroneScout — King on a central file (d/e) with a knight starting on the rim (a/h).
The king starts on d1, the rooks on a1 and f1, the queen on e1.
The kingside rook already stands on f1, so castling short moves only the king, from d1 to g1.
The bishops stand on b1 and g1; their long diagonals reach h7 and a7 once the c- and f-pawns step aside.
The second rank carries 2 pawns with no defender at all: b2, g2.
The setup belongs to the ThroneScout family; read right to left it becomes position 236.
The engine's main line opens with f4.
Morozov Balance Index: 20 of 100 — class D — largest edge. Engine evaluation of the starting position: +37 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #636Provenance
Mined from the project's engine self-play games.
Pack 006 · SP-636
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