Mate in 3: queen to b8 (c7·2)
c9-28318naming 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 c7, knight a4, pawn b2 h3.
Black: king a6, rook b8, pawn b4 h4 c5 g5.
5 white and 6 black pieces are on the board; the puzzle position arises after move 37.
The position in numbers
White are ahead by 5 points of material (14 against 9; 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 a6.
It is White to move on move 37, with 27 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 2 pawns, Black 4. Files fully open (no pawns of either colour): a, d, e, f — natural highways for the rooks and queen. Half-open for White: c, g.
The White king has 4 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
37. Qxb8 Ka5 38. b3 c4 39. Qb6#
Why it works
- Best move. queen to b8 is exactly what the engine plays (#2).
- pawn to b3 develops smoothly.
- Precise: queen to b6 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Ka5, then b3 and you win the rook.
Move by move
- 37. Qxb8 — queen to b8 (capture)
- Ka5 — king to a5
- 38. b3 — pawn to b3
- c4 — pawn to c4
- 39. Qb6# — queen to b6 and it is checkmate
Types in this puzzle
Supported queen mate
The queen delivers mate face to face, protected by a friend.
The supported queen mate is the most common pattern of all: the queen lands next to the king and mates because a friendly piece or pawn protects her. The king is helpless — capturing is impossible, and the queen covers every neighboring square herself. Hunt for a protected square beside the enemy king: a knight, bishop or pawn eyeing it turns her invasion into mate. Verify one thing — that the square really is defended, or the king eats her.
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.
Queen endgame
Queens on an open board — precision above all.
Queen endgames are treacherous: the queen reaches everywhere, and one slip turns a win into perpetual check. The signs are few pawns, exposed kings, and checks hanging in the air. Tuck your king away early, and use your own checks to bring the queen closer or push your passer with tempo. The typical mistake is grabbing pawns while leaving your king exposed to endless checks.
About this position
These pieces come from starting position #841.
SP-841 · RampartScout — A wing-file king (b or g) and at least one corner knight: the rarest of the six families, just 72 positions.
The king starts on b1, the rooks on a1 and f1, the queen on g1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
The bishops stand on d1 and e1; their long diagonals reach h5 and a5 once the e- and d-pawns step aside.
The pawn on b2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the RampartScout family; read right to left it becomes position 121.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 59 of 100 — class B — balanced. Engine evaluation of the starting position: +24 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #841Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-841
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