Mate in 3: queen to g7 (d7)
c9-26451naming 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 g2, queen d7, knight f5, pawn f2 f3 a4 g4.
Black: king g5, queen c4, knight c6, pawn d3 a5 b5.
7 white and 6 black pieces are on the board; the puzzle position arises after move 38.
The position in numbers
White are ahead by 1 points of material (16 against 15; 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 g5.
It is White to move on move 38, with 32 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 3. Files fully open (no pawns of either colour): c, e, h — natural highways for the rooks and queen. Half-open for White: b, d.
The White king has 6 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
38. Qg7+ Kf4 39. Qh6+ Ke5 40. Qd6#
Why it works
- Best move. queen to g7 is exactly what the engine plays (#2).
- Spot on — queen to h6 (#1).
- Precise: queen to d6 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Kf4, then Qh6+ and you stay on top.
Move by move
- 38. Qg7+ — queen to g7 with check
- Kf4 — king to f4
- 39. Qh6+ — queen to h6 with check
- Ke5 — king to e5
- 40. Qd6# — queen to d6 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 #521.
SP-521 · BastionGuard — Off-centre king (c/f), no knight on the a- or h-file.
The king starts on f1, the rooks on a1 and h1, the queen on c1.
Castling ends where it always does: king to g1 and rook to f1 on the short side, king to c1 and rook to d1 on the long one.
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 g2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the BastionGuard family; read right to left it becomes position 537.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 95 of 100 — class A — most balanced. Engine evaluation of the starting position: +9 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #521Provenance
Mined from the project's engine self-play games.
Pack 013 · SP-521
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