Mate in 3: queen to g7 (h8)
c9-28259naming 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.
A fork made possible by the Chess960 piece placement.
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.
A set-up fork needs one preparing move before the fork lands — a check that drives the king onto the forking square, or a capture that lines the targets up. Find the preparation first, then the fork it makes possible.
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 d1, queen h8, rook c1 h1, bishop a1, knight c3 e5, pawn d2 a3 b3 e3 c4.
Black: king e7, rook e8 f8, bishop f2 e4, knight a5, pawn g3 c5 b6 e6 a7 d7 g7.
12 white and 13 black pieces are on the board; the puzzle position arises after move 22.
The position in numbers
White are ahead by 7 points of material (33 against 26; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on d1, the black king on e7.
It is White to move on move 22, with 40 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 7. Files fully open (no pawns of either colour): f, h — natural highways for the rooks and queen. Half-open for White: g.
Black hold the bishop pair, an edge in open lines. The White king has 1 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
22. Qxg7+ Rf7 23. Qxf7+ Kd6 24. Nb5#
Why it works
- Great move! queen to g7 keeps the pressure (#2).
- Spot on — queen to f7 (#1).
- Precise: knight to b5 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Rf7, then Qxf7+ and you win the rook.
Move by move
- 22. Qxg7+ — queen to g7 (capture) with check
- Rf7 — rook to f7
- 23. Qxf7+ — queen to f7 (capture) with check
- Kd6 — king to d6
- 24. Nb5# — knight to b5 and it is checkmate
Types in this puzzle
Knight mate
The knight lands the killing blow from its unique angle.
In a knight mate the final blow comes from the knight — the only piece whose check can never be blocked. That makes it lethal against a cramped king: only a king move or capturing the knight itself can help. The sign: the squares around the king are occupied or covered, and there is a hop from which the knight checks while staying untouchable. Bring the knight over early — it is slower than the long-range pieces, but its strike cannot be parried.
Setup fork
The random setup allows a fork that classical chess never sees.
A setup fork is a double attack that exists only because of the unusual starting squares — in classical chess these targets never stand side by side. Look for pairs of undefended pieces on your opponent's back rank and for squares from which a knight or pawn hits both at once. Such forks usually appear within the first moves, before the pieces disperse. In every new position, note right away which starting pieces are defended by no one.
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 #177.
SP-177 · BastionGuard — King shifted to c or f, knights kept clear of the edges — 168 positions in all.
The king starts on f1, the rooks on c1 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: a2.
The setup belongs to the BastionGuard family; read right to left it becomes position 779.
The engine's main line opens with g4.
Morozov Balance Index: 8 of 100 — class D — largest edge. Engine evaluation of the starting position: +45 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #177Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-177
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