Mate in 2: queen to c8 (a6·3)
c9-22755naming 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 2: the first move creates an unstoppable threat, the second delivers mate.
A fork made possible by the Chess960 piece placement.
Difficulty 1450 ShuffleRating — club-player level.
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.
Mate in two usually opens with a forcing move — a check, a capture or an unstoppable threat — that strips the king of squares or defenders, so the follow-up mate becomes unavoidable. Look for the first move that leaves the opponent only losing replies.
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 a6, rook c1 f1, knight g1 d6, pawn a2 b2 d2 e2 h2 c3.
Black: king d8, queen g5, rook b8 f8, bishop c7 e8, pawn f5 d7 e7 h7.
12 white and 10 black pieces are on the board; the puzzle position arises after move 16.
The position in numbers
White are ahead by 2 points of material (31 against 29; 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 d8.
It is White to move on move 16, with 44 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 4. Files fully open (no pawns of either colour): g — natural highways for the rooks and queen. Half-open for White: f.
Black 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
16. Qc8+ Rxc8 17. Nb7#
Why it works
- Great move! queen to c8 keeps the pressure (#1).
- Well found: knight to b7 (#).
- The line ends in a forced mate in 2.
- If instead Rxc8, then Nb7# and it is mate.
Move by move
- 16. Qc8+ — queen to c8 with check
- Rxc8 — rook to c8 (capture)
- 17. Nb7# — knight to b7 and it is checkmate
Types in this puzzle
Smothered mate
The king is buried under its own pieces — only a knight can reach it.
The smothered mate suffocates a king buried under its own army: every neighboring square is blocked by friendly pieces, and the knight — needing no open lines — delivers the blow. The classic mechanism: knight check, king hides in the corner, a queen sacrifice forces a rook to plug the last hole, and the knight mates. Look for a cornered king surrounded by its own pieces and a knight one hop away. Do not mourn the queen — she only opens the door.
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 2
A forced checkmate in two moves.
Mate in two: your move, any reply, then the mating blow. Start with the most forcing first moves — checks and sacrifices that shrink the opponent's options to almost nothing. Against every single reply you must have a mate ready, so check them all without exception. The common failure is analyzing the pretty defense and forgetting the boring one.
About this position
These pieces come from starting position #376.
SP-376 · ThroneScout — A knight starts on the edge (a/h) and the king sits centrally on d or e; the mirror twin stays in this family too.
The king starts on d1, the rooks on c1 and f1, the queen on h1.
Castling long simply swaps the two pieces: the king on d1 and the rook on c1 trade places.
The bishops stand on b1 and e1; their long diagonals reach h7 and a5 once the c- and d-pawns step aside.
One second-rank pawn starts with no defender at all: b2.
The setup belongs to the ThroneScout family; read right to left it becomes position 301.
The engine's main line opens with O-O-O, bringing the king out to c1.
Morozov Balance Index: 72 of 100 — class B — balanced. Engine evaluation of the starting position: +20 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #376Provenance
Mined from the project's engine self-play games.
Pack 011 · SP-376
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