Mate in 3: queen to c6 (d5)
c9-12726naming 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 2170 ShuffleRating — expert level — few solve it at first try.
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 f1, queen d5, rook g1 d3, pawn e2 f2 a3 g3 b4 d4 h4.
Black: king c8, bishop b8, pawn a4 b6 c7.
11 white and 5 black pieces are on the board; the puzzle position arises after move 29.
The position in numbers
White are ahead by 20 points of material (26 against 6; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on f1, the black king on c8.
It is White to move on move 29, with 41 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 3. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: c.
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
29. Qc6 b5 30. Re3 Ba7 31. Re8#
Why it works
- Sensible development: queen to c6.
- rook to e3 develops smoothly.
- Precise: rook to e8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead b5, then Re3 and you stay on top.
Move by move
- 29. Qc6 — queen to c6
- b5 — pawn to b5
- 30. Re3 — rook to e3
- Ba7 — bishop to a7
- 31. Re8# — rook to e8 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.
Absolute pin
A piece is pinned against its king — it cannot legally move.
An absolute pin freezes a piece on the line between its own king and your long-range attacker: moving it is simply illegal. The pattern is three units on one straight line — your bishop, rook or queen, an enemy piece, and the enemy king behind it. A pinned piece neither attacks nor defends anything: treat it as if it were off the board. Pile up on it, ideally with a pawn, because running away is against the rules.
Quiet move
No check, no capture — yet this modest move decides the game.
A quiet move gives no check and takes nothing — yet it decides the game by creating an unstoppable threat or stealing the king's last square. This is the hardest class of moves: the eye hunts for loud blows while a modest shift does the winning. The clue: every forcing try runs into a defense, so seek the move that strengthens the threat or takes squares away. Train yourself to ask: what if I neither capture nor check, but quietly improve?
About this position
These pieces come from starting position #80.
SP-80 · BastionGuard — A c- or f-file king and two knights on inner files (b–g).
The king starts on f1, the rooks on e1 and g1, the queen on h1.
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: d2.
The setup belongs to the BastionGuard family; read right to left it becomes position 879.
The engine's main line opens with g4.
Morozov Balance Index: 1 of 100 — class D — largest edge. Engine evaluation of the starting position: +83 centipawns for White (depth 43, 400 000 000 nodes).
In 50 self-play games White scored 56.0% (95% CI 42.3–68.8%).
Explore position #80Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-80
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