Mate in 3: queen to b5 (a4)
c9-26067naming 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.
Mate in 3: a forced sequence that ends in checkmate.
Difficulty 1630 ShuffleRating — for advanced tacticians.
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.
In a mate in three every move must be forcing; the defender should never get a free tempo. Find the check or threat that herds the king, calculate the single defence to each, and confirm the net closes on the third move.
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 a4, bishop a1, knight d4 d6, pawn a2 e2 f3 g3 b4 c5.
Black: king d7, rook f8, knight b5, pawn f6 g6 a7 g7.
11 white and 7 black pieces are on the board; the puzzle position arises after move 25.
The position in numbers
White are ahead by 12 points of material (24 against 12; 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 d7.
It is White to move on move 25, with 35 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 4. Files fully open (no pawns of either colour): d, h — natural highways for the rooks and queen.
The White king has 5 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
25. Qxb5+ Kd8 26. Qb7 f5 27. Ne6#
Why it works
- Best move. queen to b5 is exactly what the engine plays (#2).
- queen to b7 develops smoothly.
- Precise: knight to e6 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Kd8, then Qb7 and you win the knight.
Move by move
- 25. Qxb5+ — queen to b5 (capture) with check
- Kd8 — king to d8
- 26. Qb7 — queen to b7
- f5 — pawn to f5
- 27. Ne6# — knight to e6 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.
Counter-strike
Don't defend — answer the threat with a bigger one.
The counter-strike: instead of defending against the threat, you answer with a bigger threat of your own. While your opponent grabs a pawn, you deliver mate — the arithmetic favors you. Look for a counter when direct defenses fail: do you have a check, an attack on the queen, a mating threat? The beginner's error is meeting every threat with a reflexive defense without checking the counterattacking resources first.
About this position
These pieces come from starting position #576.
SP-576 · BastionScout — King off-centre on c or f with a knight starting on the rim (a/h).
The king starts on f1, the rooks on d1 and g1, the queen on c1.
Castling short simply swaps the two pieces: the king on f1 and the rook on g1 trade places.
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 BastionScout family; read right to left it becomes position 287.
The engine's main line opens with c4.
Morozov Balance Index: 100 of 100 — class A — most balanced. Engine evaluation of the starting position: 0 centipawns for White (depth 49, 400 000 000 nodes).
In 50 self-play games White scored 50.0% (95% CI 36.6–63.4%).
Explore position #576Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-576
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