Mate in 1: knight to f7 (h6·6)
li-054Pknaming tag (square·N)Opens in the app if installed, otherwise downloads the APK.
The tactical motive
Mate in 1: find the move after which the enemy king has no escape.
Difficulty 1013 ShuffleRating — club-player level.
White to move — find the best continuation
How to recognize this tactic
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.
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 c1, rook d1 h1, knight g1 h6, pawn a2 g2 h2 b3 c3.
Black: king h8, queen a5, rook a8 g8, knight e3 b8, pawn e5 c6 a7 b7 g7 h7.
10 white and 12 black pieces are on the board; the puzzle position arises after move 21.
The position in numbers
Black are ahead by 10 points of material (21 against 31; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c1, the black king on h8.
It is White to move on move 21, with 27 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 6. Files fully open (no pawns of either colour): d, f — natural highways for the rooks and queen. Half-open for White: e.
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
21. Nf7#
Why it works
- Great move! knight to f7 keeps the pressure (#).
- The line ends in a forced mate in 1.
Move by move
- 21. Nf7# — knight to f7 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.
Provenance
Derived from the Lichess puzzle database (CC0).
Verified by Stockfish at depth 20+.
Solution forcedness confirmed (verified).
Pack 006
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