Mate in 3: queen to a8 (a6)
c9-28245naming 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 c1, queen a6, rook e1 b3, bishop b7, knight d3, pawn c2 h2 f4 b5.
Black: king d8, queen d4, rook f5, pawn d5 c7 g7 h7.
10 white and 7 black pieces are on the board; the puzzle position arises after move 25.
The position in numbers
White are ahead by 11 points of material (29 against 18; 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 d8.
It is White to move on move 25, with 47 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 4. Files fully open (no pawns of either colour): a, e — natural highways for the rooks and queen. Half-open for White: d, 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
25. Qa8+ Kd7 26. Bc6+ Kd6 27. Qd8#
Why it works
- Best move. queen to a8 is exactly what the engine plays (#2).
- Spot on — bishop to c6 (#1).
- Precise: queen to d8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Kd7, then Bc6+ and you stay on top.
Move by move
- 25. Qa8+ — queen to a8 with check
- Kd7 — king to d7
- 26. Bc6+ — bishop to c6 with check
- Kd6 — king to d6
- 27. Qd8# — queen to d8 and it is checkmate
Types in this puzzle
Ladder mate
Two heavy pieces climb line by line, cutting off every retreat.
The ladder mate uses two heavy pieces climbing rung by rung: one cuts the king off along a line, the other checks on the next line, driving him toward the edge. It is the classic two-rook technique — check, the king retreats one rank, the other rook checks, until mate on the last rank. The only danger is the king creeping close enough to attack one of your rooks. If it does, simply slide that rook to the far side of the same line.
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 #781.
SP-781 · BastionScout — A c- or f-file king with at least one knight out on the edge.
The king starts on c1, the rooks on b1 and f1, the queen on a1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
The bishops stand on d1 and g1; their long diagonals reach h5 and a7 once the e- and f-pawns step aside.
The pawn on d2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the BastionScout family; read right to left it becomes position 184.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 40 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +29 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #781Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-781
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