Winning blow: knight to a7 (b5)
c9-26250naming 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 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.
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 d5, rook d1 c3, knight h1 b5, pawn a2 b2 h2 d4 f4.
Black: king c8, queen e7, rook b8 h8, knight a6 h6, pawn g4 f5 c6 a7 c7 g7.
11 white and 12 black pieces are on the board; the puzzle position arises after move 21.
The position in numbers
Black are ahead by 1 points of material (30 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 c8.
It is White to move on move 21, with 46 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 6. Files fully open (no pawns of either colour): e — natural highways for the rooks and queen. Half-open for White: c, g.
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. Nxa7+ Kb7 22. Nxc6 Qd6 23. Qb5+ Kc8 24. Qxa6+
Why it works
- Great move! knight to a7 keeps the pressure (+6.1).
- Well found: knight to c6 (+5.9).
- Precise: queen to b5 is the top choice (+6.2).
- Best move. queen to a6 is exactly what the engine plays (+6.1).
- You win a piece — the knight.
- If instead Kb7, then Nxc6 and you stay on top.
Move by move
- 21. Nxa7+ — knight to a7 (capture) with check
- Kb7 — king to b7
- 22. Nxc6 — knight to c6 (capture)
- Qd6 — queen to d6
- 23. Qb5+ — queen to b5 with check
- Kc8 — king to c8
- 24. Qxa6+ — queen to a6 (capture) with check
Types in this puzzle
Win the pinned piece
The pinned piece cannot run — attack it again and win it.
A pinned piece cannot flee, which means you can win it outright by attacking it one more time. Count attackers against defenders: if you outnumber them, the piece is yours. The best extra attacker is a pawn, since it costs less than anything it might capture. Do not rush the capture — build up the pressure first, then harvest.
About this position
These pieces come from starting position #618.
SP-618 · 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 g1, the queen on c1.
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 e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the ThroneScout family; read right to left it becomes position 245.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 20 of 100 — class D — largest edge. Engine evaluation of the starting position: +37 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #618Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-618
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