Winning blow: queen to b3 (c4·2)
c9-18683naming 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 1110 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 g1, queen c4, bishop c1, knight c2 d2, pawn a2 g2 h2 d3 b4 e6.
Black: king g8, queen e8, rook d8, bishop e7, pawn d4 b5 h5 g6 a7 c7.
11 white and 10 black pieces are on the board; the puzzle position arises after move 24.
The position in numbers
White are ahead by 1 points of material (24 against 23; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on g1, the black king on g8.
It is White to move on move 24, with 29 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 6. Files fully open (no pawns of either colour): f — natural highways for the rooks and queen. Half-open for White: c.
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
24. Qb3 a5 25. bxa5
Why it works
- Great move! queen to b3 keeps the pressure (+3.1).
- Spot on — pawn to a5 (+3.3).
- You reach a winning position (+3.3).
- If instead a5, then bxa5 and you stay on top.
Move by move
- 24. Qb3 — queen to b3
- a5 — pawn to a5
- 25. bxa5 — pawn to a5 (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 #613.
SP-613 · BastionScout — A c- or f-file king with at least one knight out on the edge.
The king starts on f1, the rooks on a1 and g1, the queen on e1.
Castling short simply swaps the two pieces: the king on f1 and the rook on g1 trade places.
The bishops stand on c1 and d1; their long diagonals reach h6 and h5 once the d- and e-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 250.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 94 of 100 — class A — most balanced. Engine evaluation of the starting position: +10 centipawns for White (depth 48, 400 000 000 nodes).
Explore position #613Provenance
Mined from the project's engine self-play games.
Pack 007 · SP-613
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