Winning blow: knight to d6 (e4·17)
c9-26391naming 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 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.
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 f1, queen b1, rook c1 g1, bishop d1, knight e4 h5, pawn a2 f2 g2 h2 b3 e3 c4 d4.
Black: king f8, queen b8, rook d6 h8, bishop d8 e8, knight b6 g6, pawn h4 a5 b5 e6 f7 g7.
15 white and 14 black pieces are on the board; the puzzle position arises after move 13.
The position in numbers
Black are ahead by 1 points of material (36 against 37; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on f1, the black king on f8.
It is White to move on move 13, with 36 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 8 pawns, Black 6. No file is fully open, so the heavy pieces have to be pried in.
Black hold the bishop pair, an edge in open lines. 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
13. Nxd6 Qxd6 14. c5 Qxh2 15. cxb6
Why it works
- Brilliant! The knight on d6 is a sacrifice that works — you stand better (+2.5).
- Well found: pawn to c5 (+2.8).
- Strong! pawn to b6 is the sharp choice (+2.9).
- You win a piece — the rook.
- If instead Qxd6, then c5 and you stay on top.
Move by move
- 13. Nxd6 — knight to d6 (capture)
- Qxd6 — queen to d6 (capture)
- 14. c5 — pawn to c5
- Qxh2 — queen to h2 (capture)
- 15. cxb6 — pawn to b6 (capture)
Types in this puzzle
Decoy
A sacrifice lures the king or a piece onto a fatal square.
A decoy is the mirror image of deflection: you sacrifice to drag the king or a piece onto a fatal square. The classic is a queen or rook sac whose capture pulls the king into a knight fork, a discovered check or mate. Find the square where the target will be hit, then find the offer it cannot refuse. Calculate to the very end — a decoy only works when the follow-up is forced.
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.
Development punish
Half the army still asleep — the attack breaks through.
Punishing lazy development: half of your opponent's army is asleep on its starting squares, which means you outnumber him where the fight is. Count not the pieces on the board but the pieces in play — if five or more of his pieces have never moved, look for a forcing attack. The sign is a development lead plus open lines toward his king. Strike immediately: give him two quiet moves and the advantage evaporates.
About this position
These pieces come from starting position #313.
SP-313 · BastionScout — A c- or f-file king with at least one knight out on the edge.
The king starts on f1, the rooks on c1 and g1, the queen on b1.
Castling short simply swaps the two pieces: the king on f1 and the rook on g1 trade places.
The bishops stand on d1 and e1; their long diagonals reach h5 and a5 once the e- and d-pawns step aside.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the BastionScout family; read right to left it becomes position 361.
The engine's main line opens with c4.
Morozov Balance Index: 21 of 100 — class D — largest edge. Engine evaluation of the starting position: +36 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #313Provenance
Mined from the project's engine self-play games.
Pack 011 · SP-313
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