Attack on the uncastled king: knight to b7 (c5·3)
c9-01853naming 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 c2, queen h1, rook a1 e1, bishop g1 g2, knight c5, pawn a2 b2 d2 e2 h2 c3 f4.
Black: king d8, queen g8, rook a8 e8, bishop d5 f8, knight c6 c8, pawn e4 a7 b7 c7 d7 e7 h7.
14 white and 15 black pieces are on the board; the puzzle position arises after move 11.
The position in numbers
Black are ahead by 3 points of material (35 against 38; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c2, the black king on d8.
It is White to move on move 11, with 36 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 7. Files fully open (no pawns of either colour): g — natural highways for the rooks and queen.
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
11. Nxb7#
Why it works
- Great move! knight to b7 keeps the pressure (#).
- The line ends in a forced mate in 1.
Move by move
- 11. Nxb7# — knight to b7 (capture) 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.
Only move
Everything else loses — find the only move that holds.
An only move is a position where everything loses except one single continuation. You cannot play "by hand" here: run through fundamentally different defenses — run away, block, trade, counterattack — and discard the ones that fail. The hallmark of these puzzles is that the obvious moves lose quickly while the solution often looks strange. First understand exactly what the threat is — then the one saving move reveals itself.
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.
About this position
These pieces come from starting position #478.
SP-478 · ThroneGuard — A centre-file king with no knight on the edge; a position and its mirror twin always share this family.
The king starts on d1, the rooks on a1 and e1, the queen on h1.
Castling ends where it always does: king to g1 and rook to f1 on the short side, king to c1 and rook to d1 on the long one.
The bishops stand on f1 and g1; their long diagonals reach a6 and a7 once the e- and f-pawns step aside.
One second-rank pawn starts with no defender at all: b2.
The setup belongs to the ThroneGuard family; read right to left it becomes position 676.
The engine's main line opens with Nc3, bringing the knight out to c3.
Morozov Balance Index: 24 of 100 — class D — largest edge. Engine evaluation of the starting position: +35 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #478Provenance
Mined from the project's engine self-play games.
Verified by Stockfish at depth 20+.
Solution forcedness confirmed (verified).
Pack 001 · SP-478
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