Mate in 2: queen to a7 (f2·3)
c9-13395naming 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 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.
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 b1, queen f2, rook a1 g2, bishop g1, knight d3, pawn c2 h2 g3 a4 f5.
Black: king b8, queen d8, rook c6 e8, bishop c3, knight c4, pawn a5 b7 c7 d7 h7.
11 white and 11 black pieces are on the board; the puzzle position arises after move 22.
The position in numbers
Material is level — 30 points of pieces on each side (pawn = 1, knight and bishop = 3, rook = 5, queen = 9).
The white king stands on b1, the black king on b8.
It is White to move on move 22, with 27 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 5. Files fully open (no pawns of either colour): e — natural highways for the rooks and queen. Half-open for White: b, d.
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
22. Qa7+ Kc8 23. Qa8#
Why it works
- Great move! queen to a7 keeps the pressure (#1).
- Well found: queen to a8 (#).
- The line ends in a forced mate in 2.
- If instead Kc8, then Qa8# and it is mate.
Move by move
- 22. Qa7+ — queen to a7 with check
- Kc8 — king to c8
- 23. Qa8# — queen to a8 and it is checkmate
Types in this puzzle
Back-rank mate
The king is locked behind its own pawns — a heavy piece strikes the last rank.
The back-rank mate strikes a king locked behind its own unmoved pawns when a rook or queen crashes onto the last rank. The signs: no escape hole in front of the king, and the back rank guarded by a single piece or by nobody at all. Often that lone guard is deflected or traded off first, and only then comes the invasion. In your own games, make luft in time — one pawn move prevents a sudden catastrophe.
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.
Relative pin
A piece shields a more valuable one behind it — moving it loses material.
In a relative pin the piece shields not its king but something valuable behind it, usually the queen. Moving is legal but costly, because the piece behind falls. Look for three units on one line: your long-range piece, a cheaper enemy piece, and an expensive one hiding behind. Beware the classic trap — a relatively pinned piece can still move with check or a bigger threat, so verify before you cash in.
About this position
These pieces come from starting position #735.
SP-735 · 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 f1, the queen on d1.
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.
The pawn on b2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the RampartGuard family; read right to left it becomes position 416.
The engine's main line opens with a4.
Morozov Balance Index: 20 of 100 — class D — largest edge. Engine evaluation of the starting position: +37 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #735Provenance
Mined from the project's engine self-play games.
Pack 010 · SP-735
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