Attack on the uncastled king: knight to f5 (e3·22)
c9-22332naming 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 1480 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 f1, queen e2, rook e1, bishop g2 c3, knight e3 f3, pawn a2 f2 h2 b3 g3 c4 d5.
Black: king e8, queen c8, rook a8 f8, bishop g7, knight f6 d8, pawn a3 c6 d6 g6 h6 b7 e7 f7.
14 white and 15 black pieces are on the board; the puzzle position arises after move 16.
The position in numbers
Black are ahead by 3 points of material (33 against 36; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on f1, the black king on e8.
It is White to move on move 16, with 36 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 8. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: e.
White hold the bishop pair, an edge in open lines. 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
16. Nf5 O-O 17. Nxe7+ Kh7 18. Nxc8
Why it works
- Great move! knight to f5 keeps the pressure (+5.3).
- Well found: knight to e7 (+5.3).
- Precise: knight to c8 is the top choice (+5.3).
- You win a piece — the queen.
- If instead O-O, then Nxe7+ and you stay on top.
Move by move
- 16. Nf5 — knight to f5
- O-O — king to f8
- 17. Nxe7+ — knight to e7 (capture) with check
- Kh7 — king to h7
- 18. Nxc8 — knight to c8 (capture)
Types in this puzzle
Royal fork
A fork with check: the king must move, and the second piece is lost.
A royal fork is a fork with check — one of the two targets is the king itself. The check must be answered first, so nobody is left to rescue the second piece. Look for squares where your piece gives check and simultaneously attacks an undefended queen or rook. It is the most reliable fork of all, because your opponent literally has no choice.
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.
Absolute pin
A piece is pinned against its king — it cannot legally move.
An absolute pin freezes a piece on the line between its own king and your long-range attacker: moving it is simply illegal. The pattern is three units on one straight line — your bishop, rook or queen, an enemy piece, and the enemy king behind it. A pinned piece neither attacks nor defends anything: treat it as if it were off the board. Pile up on it, ideally with a pawn, because running away is against the rules.
About this position
These pieces come from starting position #599.
SP-599 · ThroneGuard — King home on d or e, knights kept off the a- and h-files — the family of the standard starting array.
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.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the ThroneGuard family; read right to left it becomes position 258.
The engine's main line opens with Nf3, bringing the knight out to f3.
Morozov Balance Index: 69 of 100 — class B — balanced. Engine evaluation of the starting position: +21 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #599Provenance
Mined from the project's engine self-play games.
Pack 011 · SP-599
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