Attack on the uncastled king: rook to a8 (a1·7)
c9-16102naming 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.
Uncastled king: the enemy king is stuck in the centre — punish it before it castles.
Winning tactic: there is a move that gains a decisive advantage — find it.
Difficulty 1560 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.
An uncastled king in the centre is a standing target. Look for ways to open the central files and diagonals against it with checks and threats before it can shelter — every tempo the king spends in the middle is a chance for a combination.
This position hides a concrete tactic that wins material or mates. Start with the most forcing candidate moves — checks, captures and threats — and calculate each to a clear end before choosing; the winning line is usually the one the opponent cannot meet.
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 g1, queen d5, rook a1 h3, knight d3 g3, pawn e2 f2 g2 b4 d4 h4.
Black: king g8, queen a8, rook h8, knight g6, pawn c5 h5 b6 e7 f7 g7.
12 white and 10 black pieces are on the board; the puzzle position arises after move 22.
The position in numbers
White are ahead by 8 points of material (31 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 g1, the black king on g8.
It is White to move on move 22, with 53 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 6. Files fully open (no pawns of either colour): a — natural highways for the rooks and queen. Half-open for White: c.
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. Rxa8+ Nf8 23. Rxf8+ Kxf8 24. Qd8#
Why it works
- Great move! rook to a8 keeps the pressure (#2).
- Spot on — rook to f8 (#1).
- Precise: queen to d8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Nf8, then Rxf8+ and you win the queen.
Move by move
- 22. Rxa8+ — rook to a8 (capture) with check
- Nf8 — knight to f8
- 23. Rxf8+ — rook to f8 (capture) with check
- Kxf8 — king to f8 (capture)
- 24. Qd8# — queen to d8 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 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.
Uncastled king
The king lingered in the middle — punish the delay.
Punishing the uncastled king: your opponent delayed castling, and now his king is stuck on its starting square under fire. In Chess960 this is deadlier than in classical chess — the king may start in the center or near the edge, and the familiar defensive setups simply do not apply. The signs: the victim still holds castling rights, and the files toward his king are half-open. Open lines before the king manages to hide.
About this position
These pieces come from starting position #401.
SP-401 · RampartGuard — A wing king (b/g) with no knight on the a- or h-file.
The king starts on g1, the rooks on b1 and h1, the queen on c1.
The king already stands on its castled square, so castling short moves only the rook, from h1 to f1.
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 RampartGuard family; read right to left it becomes position 747.
The engine's main line opens with b4.
Morozov Balance Index: 96 of 100 — class A — most balanced. Engine evaluation of the starting position: -7 centipawns for White (depth 41, 400 000 000 nodes).
In 50 self-play games White scored 49.0% (95% CI 35.7–62.4%).
Explore position #401Provenance
Mined from the project's engine self-play games.
Pack 011 · SP-401
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