Attack on the uncastled king: knight to g7 (h5·8)
c9-07229naming 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 3: a forced sequence that ends in checkmate.
Uncastled king: the enemy king is stuck in the centre — punish it before it castles.
Difficulty 1630 ShuffleRating — for advanced tacticians.
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.
In a mate in three every move must be forcing; the defender should never get a free tempo. Find the check or threat that herds the king, calculate the single defence to each, and confirm the net closes on the third move.
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 e1, queen h7, rook a1 f1, bishop c2 e3, knight c1 h5, pawn b2 d2 e2 g2 c3 h3 a4 f4.
Black: king e8, queen b7, rook a8 f8, bishop d5 d8, knight d6 h8, pawn c5 b6 e6 f6 a7 d7 g7.
16 white and 15 black pieces are on the board; the puzzle position arises after move 12.
The position in numbers
White are ahead by 1 points of material (39 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 e1, the black king on e8.
It is White to move on move 12, with 45 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 8 pawns, Black 7. No file is fully open, so the heavy pieces have to be pried in.
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
12. Nxg7+ Ke7 13. Nf5+ Ke8 14. Nxd6#
Why it works
- Great move! knight to g7 keeps the pressure (#2).
- Well found: knight to f5 (#1).
- Precise: knight to d6 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Ke7, then Nf5+ and you stay on top.
Move by move
- 12. Nxg7+ — knight to g7 (capture) with check
- Ke7 — king to e7
- 13. Nf5+ — knight to f5 with check
- Ke8 — king to e8
- 14. Nxd6# — knight to d6 (capture) and it is checkmate
Types in this puzzle
Knight mate
The knight lands the killing blow from its unique angle.
In a knight mate the final blow comes from the knight — the only piece whose check can never be blocked. That makes it lethal against a cramped king: only a king move or capturing the knight itself can help. The sign: the squares around the king are occupied or covered, and there is a hop from which the knight checks while staying untouchable. Bring the knight over early — it is slower than the long-range pieces, but its strike cannot be parried.
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 #605.
SP-605 · ThroneScout — King in the middle of the rank, with a knight already committed to the corner.
The king starts on e1, the rooks on a1 and f1, the queen on b1.
The kingside rook already stands on f1, so castling short moves only the king, from e1 to g1.
The bishops stand on d1 and g1; their long diagonals reach h5 and a7 once the e- and f-pawns step aside.
One second-rank pawn starts with no defender at all: g2.
The setup belongs to the ThroneScout family; read right to left it becomes position 264.
The engine's main line opens with Ng3, bringing the knight out to g3.
Morozov Balance Index: 7 of 100 — class D — largest edge. Engine evaluation of the starting position: +47 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #605Provenance
Mined from the project's engine self-play games.
Verified by Stockfish at depth 20+.
Solution forcedness confirmed (verified).
Pack 012 · SP-605
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