Mate in 2: queen to a6 (f1·2)
c9-15945naming 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.
Difficulty 1220 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.
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 f1, rook b1, bishop a1, knight e3 f5, pawn a2 f2 h2 b3 g3 c6.
Black: king c8, queen g6, bishop e5, knight e8 f8, pawn a5 g5 c7 f7 h7.
12 white and 10 black pieces are on the board; the puzzle position arises after move 19.
The position in numbers
White are ahead by 6 points of material (29 against 23; 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 c8.
It is White to move on move 19, with 40 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 5. Files fully open (no pawns of either colour): d, e — natural highways for the rooks and queen.
The White king has 5 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
19. Qa6+ Kd8 20. Qa8#
Why it works
- Great move! queen to a6 keeps the pressure (#1).
- Well found: queen to a8 (#).
- The line ends in a forced mate in 2.
- If instead Kd8, then Qa8# and it is mate.
Move by move
- 19. Qa6+ — queen to a6 with check
- Kd8 — king to d8
- 20. Qa8# — queen to a8 and it is checkmate
Types in this puzzle
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 #947.
SP-947 · BastionGuard — Off-centre king (c/f), no knight on the a- or h-file.
The king starts on c1, the rooks on b1 and d1, the queen on g1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
The second rank carries 2 pawns with no defender at all: a2, e2.
The setup belongs to the BastionGuard family; read right to left it becomes position 3.
The engine's main line opens with g3.
Morozov Balance Index: 31 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +32 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #947Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-947
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