Winning blow: queen to a5 (a4·2)
c9-27205naming 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 h2, queen a4, rook f1 a6, bishop a1 c4, knight d6, pawn a2 g2 g4.
Black: king d8, rook c8 f8, pawn f2 b4 e5 g6 d7 h7.
10 white and 9 black pieces are on the board; the puzzle position arises after move 25.
The position in numbers
White are ahead by 15 points of material (31 against 16; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on h2, the black king on d8.
It is White to move on move 25, with 46 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 3 pawns, Black 6. Files fully open (no pawns of either colour): c — natural highways for the rooks and queen. Half-open for White: b, d, e, f, h.
White 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
25. Qa5+ Ke7 26. Qxe5+ Kd8 27. Nb7#
Why it works
- Best move. queen to a5 is exactly what the engine plays (#2).
- Spot on — queen to e5 (#1).
- Precise: knight to b7 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Ke7, then Qxe5+ and you stay on top.
Move by move
- 25. Qa5+ — queen to a5 with check
- Ke7 — king to e7
- 26. Qxe5+ — queen to e5 (capture) with check
- Kd8 — king to d8
- 27. Nb7# — knight to b7 and it is checkmate
Types in this puzzle
Knight mate
The knight lands the killing blow from its unique angle.
In a knight mate the final blow comes from the knight — the only piece whose check can never be blocked. That makes it lethal against a cramped king: only a king move or capturing the knight itself can help. The sign: the squares around the king are occupied or covered, and there is a hop from which the knight checks while staying untouchable. Bring the knight over early — it is slower than the long-range pieces, but its strike cannot be parried.
Mate in 3
A forced checkmate in three moves.
Mate in three is a forced staircase: each of your moves narrows the opponent's choices, and the third one ends the game. Look for the start among checks and sacrifices — quiet first moves are rare in mating problems, but deliciously sneaky. Keep the tree in your head: every defense gets its own branch. Do not stop calculating after move two — see the final mating picture with your own eyes.
About this position
These pieces come from starting position #290.
SP-290 · ThroneScout — The king starts on d or e while at least one knight begins in a corner.
The king starts on e1, the rooks on d1 and g1, the queen on b1.
The queenside rook already stands on d1, so castling long moves only the king, from e1 to c1.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
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 375.
The engine's main line opens with c4.
Morozov Balance Index: 16 of 100 — class D — largest edge. Engine evaluation of the starting position: +39 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #290Provenance
Mined from the project's engine self-play games.
Pack 011 · SP-290
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