Mate in 2: queen to a8 (a4)
c9-24928naming 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 1320 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 b2, queen a4, rook a1, bishop e1, pawn f2 e3 b4 d4 g4 c6.
Black: king c8, queen f3, rook d8, bishop b7 g7, pawn g3 e4 g5 b6 e6 h6 c7.
10 white and 12 black pieces are on the board; the puzzle position arises after move 30.
The position in numbers
Black are ahead by 4 points of material (23 against 27; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b2, the black king on c8.
It is White to move on move 30, with 27 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 7. Files fully open (no pawns of either colour): a — natural highways for the rooks and queen. Half-open for White: h.
Black hold the bishop pair, an edge in open lines. The White king has 7 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
30. Qa8+ Bxa8 31. Rxa8#
Why it works
- Great move! queen to a8 keeps the pressure (#1).
- Well found: rook to a8 (#).
- The line ends in a forced mate in 2.
- If instead Bxa8, then Rxa8# and it is mate.
Move by move
- 30. Qa8+ — queen to a8 with check
- Bxa8 — bishop to a8 (capture)
- 31. Rxa8# — rook to a8 (capture) 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.
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.
Royal fork
A fork with check: the king must move, and the second piece is lost.
A royal fork is a fork with check — one of the two targets is the king itself. The check must be answered first, so nobody is left to rescue the second piece. Look for squares where your piece gives check and simultaneously attacks an undefended queen or rook. It is the most reliable fork of all, because your opponent literally has no choice.
About this position
These pieces come from starting position #843.
SP-843 · RampartGuard — King pushed to the b- or g-file, knights off the edges — 144 positions here.
The king starts on b1, the rooks on a1 and d1, the queen on f1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the RampartGuard family; read right to left it becomes position 113.
The engine's main line opens with a4.
Morozov Balance Index: 40 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +29 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #843Provenance
Mined from the project's engine self-play games.
Pack 010 · SP-843
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