Mate in 3: queen to a7 (a5)
c9-22441naming 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 g2, queen a5, rook h5, bishop c4, pawn a2 b2 g3 d4.
Black: king d7, queen g7, pawn c6.
8 white and 3 black pieces are on the board; the puzzle position arises after move 39.
The position in numbers
White are ahead by 11 points of material (21 against 10; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on g2, the black king on d7.
It is White to move on move 39, with 54 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 1. Files fully open (no pawns of either colour): e, f, h — natural highways for the rooks and queen. Half-open for White: c.
The White king has 7 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
39. Qa7+ Ke8 40. Qxg7 c5 41. Rh8#
Why it works
- Best move. queen to a7 is exactly what the engine plays (#2).
- Spot on — queen to g7 (#1).
- Precise: rook to h8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Ke8, then Qxg7 and you win the queen.
Move by move
- 39. Qa7+ — queen to a7 with check
- Ke8 — king to e8
- 40. Qxg7 — queen to g7 (capture)
- c5 — pawn to c5
- 41. Rh8# — rook to h8 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.
Skewer
A line attack forces the valuable piece to move, exposing the one behind it.
A skewer is a pin turned inside out: the valuable piece stands in front and something cheaper hides behind it. The big piece must step aside, and you collect the one that was sheltering in its shadow. Scan for the enemy king or queen sharing a file, rank or diagonal with another enemy piece. The deadliest version comes with check — the king moves, the rook behind it dies.
About this position
These pieces come from starting position #118.
SP-118 · RampartScout — A knight in the corner and the king out on the wing (b/g); like every family, it is closed under mirror twins.
The king starts on g1, the rooks on d1 and h1, the queen on b1.
The king already stands on its castled square, so castling short moves only the rook, from h1 to f1.
The bishops stand on c1 and f1; their long diagonals reach h6 and a6 once the d- and e-pawns step aside.
The pawn on f2 is defended by the king alone — the classic soft spot of the standard setup.
The setup belongs to the RampartScout family; read right to left it becomes position 838.
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 45, 400 000 000 nodes).
Explore position #118Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-118
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