Winning blow: knight to c5 (d3·15)
c9-24986naming 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 1390 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 a6, rook a1 f1, bishop g1, knight d3, pawn b2 c2 h2 g3 d4 f4 e5.
Black: king b8, queen h6, rook d7 a8, knight e7 h8, pawn f5 e6 a7 c7 g7 h7.
13 white and 12 black pieces are on the board; the puzzle position arises after move 21.
The position in numbers
White are ahead by 1 points of material (32 against 31; 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 b8.
It is White to move on move 21, with 39 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 6. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: a.
The White king has 3 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
21. Nc5 c6 22. Ra3 Nd5 23. Qxc6 Qxf4+ 24. gxf4
Why it works
- Best move. knight to c5 is exactly what the engine plays (+10.8).
- rook to a3 develops smoothly.
- Precise: queen to c6 is the top choice (#4).
- Best move. pawn to f4 is exactly what the engine plays (#3).
- You win a piece — the queen.
- If instead c6, then Ra3 and you stay on top.
Move by move
- 21. Nc5 — knight to c5
- c6 — pawn to c6
- 22. Ra3 — rook to a3
- Nd5 — knight to d5
- 23. Qxc6 — queen to c6 (capture)
- Qxf4+ — queen to f4 (capture) with check
- 24. gxf4 — pawn to f4 (capture)
Types in this puzzle
Quiet move
No check, no capture — yet this modest move decides the game.
A quiet move gives no check and takes nothing — yet it decides the game by creating an unstoppable threat or stealing the king's last square. This is the hardest class of moves: the eye hunts for loud blows while a modest shift does the winning. The clue: every forcing try runs into a defense, so seek the move that strengthens the threat or takes squares away. Train yourself to ask: what if I neither capture nor check, but quietly improve?
About this position
These pieces come from starting position #637.
SP-637 · BastionScout — A c- or f-file king with at least one knight out on the edge.
The king starts on c1, the rooks on a1 and f1, the queen on e1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
The bishops stand on d1 and g1; their long diagonals reach h5 and a7 once the e- and f-pawns step aside.
One second-rank pawn starts with no defender at all: g2.
The setup belongs to the BastionScout family; read right to left it becomes position 232.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 39 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +21 centipawns for White (depth 44, 400 000 000 nodes).
In 50 self-play games White scored 57.0% (95% CI 43.3–69.7%).
Explore position #637Provenance
Mined from the project's engine self-play games.
Pack 010 · SP-637
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