Mate in 3: queen to g6 (b1·2)
c9-21615naming 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 e1, queen b1, rook g1, bishop c1 d5, knight g7, pawn a2 b2 e2 h2 f4 e5 f6.
Black: king h8, rook c8, knight c4, pawn a5 b5 h5 g6 e7.
13 white and 8 black pieces are on the board; the puzzle position arises after move 25.
The position in numbers
White are ahead by 17 points of material (30 against 13; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on e1, the black king on h8.
It is White to move on move 25, with 46 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 5. Files fully open (no pawns of either colour): c, d — 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 4 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
25. Qxg6 e6 26. Qxh5+ Kg8 27. Nxe6#
Why it works
- Best move. queen to g6 is exactly what the engine plays (#2).
- Spot on — queen to h5 (#1).
- Precise: knight to e6 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead e6, then Qxh5+ and you stay on top.
Move by move
- 25. Qxg6 — queen to g6 (capture)
- e6 — pawn to e6
- 26. Qxh5+ — queen to h5 (capture) with check
- Kg8 — king to g8
- 27. Nxe6# — knight to e6 (capture) and it is checkmate
Types in this puzzle
Discovered mate
A piece steps aside — and the one behind it delivers mate.
In a discovered mate the piece that moves is not the one that mates — the long-range piece behind it delivers the blow. The moving piece is completely free: it can land anywhere, ideally stealing the king's last squares or guarding key points. Look for your rook, bishop or queen lined up with the enemy king, with exactly one of your own pieces in between. When choosing the unveiling move, remember its second job — shutting the king's escape door.
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.
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.
About this position
These pieces come from starting position #215.
SP-215 · ThroneScout — King in the middle of the rank, with a knight already committed to the corner.
The king starts on e1, the rooks on d1 and g1, the queen on b1.
The queenside rook already stands on d1, so castling long moves only the king, from e1 to c1.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
The pawn on e2, f2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the ThroneScout family; read right to left it becomes position 642.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 91 of 100 — class A — most balanced. Engine evaluation of the starting position: +13 centipawns for White (depth 51, 400 000 000 nodes).
Explore position #215Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-215
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