Attack on the uncastled king: pawn to e4 (f3·37)
c9-23619naming tag (square·N)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 1200 ShuffleRating — club-player level.
White to move — find the best continuation
Position on the board
White: king d1, queen c2, rook a1 h1, bishop f1 d2, knight g1 a5, pawn b2 g2 h2 f3 d4 e5.
Black: king d8, queen b8, rook a8 h8, bishop b5 g7, knight e4 d6, pawn a4 c4 g6 a7 c7 e7 f7 h7.
14 white and 16 black pieces are on the board; the puzzle position arises after move 12.
Solution & explanation
Main line
12. fxe4 O-O 13. Nf3 Rc8 14. Bxc4 Nxc4 15. Nxc4
Why it works
- Great move! pawn to e4 keeps the pressure (+3.9).
- knight to f3 develops smoothly.
- Precise: bishop to c4 is the top choice (+3.9).
- Great move! knight to c4 keeps the pressure (+4.1).
- You win a piece — the knight.
- If instead O-O, then Nf3 and you win the knight.
Types in this puzzle
Overload
One defender guards two things — it cannot do both jobs.
Overloading exploits a defender with two jobs at once — guarding a piece and covering a mating square, for instance. It cannot do both: your first strike forces it to handle one duty and abandon the other. Find the overworked piece by asking what happens to each of its charges if it gets distracted. Then hit one target and collect the other — an overloaded defender only pretends to defend.
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.
Winning exchange
A forced series of captures on one square ends in your favour.
A winning exchange is a forced series of captures on one square that leaves you ahead in material. It is pure arithmetic: count the attackers and defenders of the square and note the value of every piece in the queue. Capture in the right order — cheap pieces first, expensive ones later — or a winning trade turns into a losing one. The classic error is stopping the count halfway and missing the opponent's final recapture.
About this position
These pieces come from starting position #506.
SP-506 · ThroneGuard — The king starts in the middle of the back rank, on d or e, and neither knight begins in a corner.
The king starts on d1, the rooks on a1 and h1, the queen on b1.
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 e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the ThroneGuard family; read right to left it becomes position 549.
The engine's main line opens with d4, putting a pawn straight into the centre.
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 #506Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-506
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