Attack on the uncastled king: knight to h7 (g5·3)
c9-04868naming 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 1: find the move after which the enemy king has no escape.
Uncastled king: the enemy king is stuck in the centre — punish it before it castles.
Difficulty 620 ShuffleRating — for beginners taking their first steps in Chess960 tactics.
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.
A mate in one hides among forcing checks. Run through every check you can give: does it cover all the king's escape squares, is the checking piece safe or supported, and can nothing block or capture it? If yes, that is the mate.
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.
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 f1, queen a1, rook e1 h1, bishop b1 c1, knight e3 g5, pawn a2 c2 f2 g2 b3 h4.
Black: king f8, queen a8, rook e8 g8, bishop d6 b7, knight d4 g6, pawn a5 c5 h5 e7 f7 g7.
14 white and 14 black pieces are on the board; the puzzle position arises after move 13.
The position in numbers
Material is level — 37 points of pieces on each side (pawn = 1, knight and bishop = 3, rook = 5, queen = 9).
The white king stands on f1, the black king on f8.
It is White to move on move 13, with 32 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): d — natural highways for the rooks and queen. Half-open for White: e.
The White king has 1 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
13. Nh7#
Why it works
- Great move! knight to h7 keeps the pressure (#).
- The line ends in a forced mate in 1.
Move by move
- 13. Nh7# — knight to h7 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.
Mate in 1
Checkmate in a single move — find it.
Mate in one: the combination is over, only the final precise shot remains. The method is simple — list every check you have and test the three escapes against each: king moves, blocks, and capturing the checker. If none of them works, it is mate. The classic blunder is falling in love with the first check you see and missing the one escape hatch.
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 #292.
SP-292 · BastionScout — A knight on the a- or h-file, king on c or f — the mirror twin lands here as well.
The king starts on f1, the rooks on e1 and g1, the queen on a1.
Castling short simply swaps the two pieces: the king on f1 and the rook on g1 trade places.
The bishops stand on b1 and c1; their long diagonals reach h7 and h6 once the c- and d-pawns step aside.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the BastionScout family; read right to left it becomes position 382.
The engine's main line opens with c4.
Morozov Balance Index: 19 of 100 — class D — largest edge. Engine evaluation of the starting position: +49 centipawns for White (depth 45, 400 000 000 nodes).
In 50 self-play games White scored 51.0% (95% CI 37.6–64.3%).
Explore position #292Provenance
Mined from the project's engine self-play games.
Verified by Stockfish at depth 20+.
Solution forcedness confirmed (verified).
Pack 001 · SP-292
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