Attack on the uncastled king: pawn to f5 (f4·5)
c9-26498naming 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 1390 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 e1, queen g1, rook d1 f1, bishop c1 c2, knight f2 b3, pawn a2 b2 e2 h2 c3 d4 f4.
Black: king e8, queen g8, rook d8 f8, bishop e6 b8, knight d7 f7, pawn g4 d5 c6 a7 b7 e7 g7 h7.
15 white and 16 black pieces are on the board; the puzzle position arises after move 9.
The position in numbers
Black are ahead by 1 points of material (38 against 39; 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 9, with 32 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: g.
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
9. f5 Nh6 10. Bxh6 Bxf5 11. Bxf5 Rxf5 12. Qxg4
Why it works
- Great move! pawn to f5 keeps the pressure (+3.5).
- Spot on — bishop to h6 (+3.4).
- Strong! bishop to f5 is the sharp choice (+3.4).
- Best move. queen to g4 is exactly what the engine plays (+3.8).
- You win a piece — the bishop.
- If instead Nh6, then Bxh6 and you win the knight.
Move by move
- 9. f5 — pawn to f5
- Nh6 — knight to h6
- 10. Bxh6 — bishop to h6 (capture)
- Bxf5 — bishop to f5 (capture)
- 11. Bxf5 — bishop to f5 (capture)
- Rxf5 — rook to f5 (capture)
- 12. Qxg4 — queen to g4 (capture)
Types in this puzzle
Decoy
A sacrifice lures the king or a piece onto a fatal square.
A decoy is the mirror image of deflection: you sacrifice to drag the king or a piece onto a fatal square. The classic is a queen or rook sac whose capture pulls the king into a knight fork, a discovered check or mate. Find the square where the target will be hit, then find the offer it cannot refuse. Calculate to the very end — a decoy only works when the follow-up is forced.
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.
Development punish
Half the army still asleep — the attack breaks through.
Punishing lazy development: half of your opponent's army is asleep on its starting squares, which means you outnumber him where the fight is. Count not the pieces on the board but the pieces in play — if five or more of his pieces have never moved, look for a forcing attack. The sign is a development lead plus open lines toward his king. Strike immediately: give him two quiet moves and the advantage evaporates.
About this position
These pieces come from starting position #356.
SP-356 · ThroneScout — The king starts on d or e while at least one knight begins in a corner.
The king starts on e1, the rooks on d1 and f1, the queen on g1.
The kingside rook already stands on f1, so castling short moves only the king, from e1 to g1.
The bishops stand on b1 and c1; their long diagonals reach h7 and h6 once the c- and d-pawns step aside.
The pawn on e2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the ThroneScout family; read right to left it becomes position 318.
The engine's main line opens with f4.
Morozov Balance Index: 51 of 100 — class B — balanced. Engine evaluation of the starting position: +26 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #356Provenance
Mined from the project's engine self-play games.
Pack 010 · SP-356
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