Mate in 3: queen to h6 (g6·2)
c9-27103naming 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 g6, rook g1, bishop d4 h7, knight b3 h3, pawn a2 e2 f2 h2 d5.
Black: king f8, rook c7, bishop b8, knight h6, pawn g4 f6 a7 d7 e7.
12 white and 9 black pieces are on the board; the puzzle position arises after move 21.
The position in numbers
White are ahead by 15 points of material (31 against 16; 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 f8.
It is White to move on move 21, with 48 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 5. Files fully open (no pawns of either colour): b, c — natural highways for the rooks and queen. Half-open for White: g.
White hold the bishop pair, an edge in open lines. 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
21. Qxh6+ Ke8 22. Qg6+ Kd8 23. Qg8#
Why it works
- Best move. queen to h6 is exactly what the engine plays (#2).
- Spot on — queen to g6 (#1).
- Precise: queen to g8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Ke8, then Qg6+ and you win the knight.
Move by move
- 21. Qxh6+ — queen to h6 (capture) with check
- Ke8 — king to e8
- 22. Qg6+ — queen to g6 with check
- Kd8 — king to d8
- 23. Qg8# — queen to g8 and it is checkmate
Types in this puzzle
Back-rank mate
The king is locked behind its own pawns — a heavy piece strikes the last rank.
The back-rank mate strikes a king locked behind its own unmoved pawns when a rook or queen crashes onto the last rank. The signs: no escape hole in front of the king, and the back rank guarded by a single piece or by nobody at all. Often that lone guard is deflected or traded off first, and only then comes the invasion. In your own games, make luft in time — one pawn move prevents a sudden catastrophe.
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 #224.
SP-224 · BastionGuard — A c- or f-file king and two knights on inner files (b–g).
The king starts on f1, the rooks on d1 and h1, the queen on e1.
The queenside rook already stands on d1, so castling long moves only the king, from f1 to c1.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
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 639.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 69 of 100 — class B — balanced. Engine evaluation of the starting position: +21 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #224Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-224
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