Mate in 3: queen to c5 (b6)
c9-28287naming 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 1760 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 c1, queen b6, rook d1, bishop g1, knight b4, pawn a2 c2 g2 h2 b3 d6.
Black: king c8, queen e8, rook d7 f8, bishop e6, knight h4, pawn a3 b7 g7 h7.
11 white and 10 black pieces are on the board; the puzzle position arises after move 24.
The position in numbers
Black are ahead by 3 points of material (26 against 29; 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 24, with 33 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): e, f — natural highways for the rooks and queen.
The White king has 2 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
24. Qc5+ Kd8 25. Qa5+ b6 26. Qa8#
Why it works
- Great move! queen to c5 keeps the pressure (#2).
- Spot on — queen to a5 (#1).
- Precise: queen to a8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Kd8, then Qa5+ and you stay on top.
Move by move
- 24. Qc5+ — queen to c5 with check
- Kd8 — king to d8
- 25. Qa5+ — queen to a5 with check
- b6 — pawn to b6
- 26. Qa8# — queen to a8 and it is checkmate
Types in this puzzle
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 #637.
SP-637 · BastionScout — A c- or f-file king with at least one knight out on the edge.
The king starts on c1, the rooks on a1 and f1, the queen on e1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
The bishops stand on d1 and g1; their long diagonals reach h5 and a7 once the e- and f-pawns step aside.
One second-rank pawn starts with no defender at all: g2.
The setup belongs to the BastionScout family; read right to left it becomes position 232.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 39 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +21 centipawns for White (depth 44, 400 000 000 nodes).
In 50 self-play games White scored 57.0% (95% CI 43.3–69.7%).
Explore position #637Provenance
Mined from the project's engine self-play games.
Pack 013 · SP-637
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