Attack on the uncastled king: pawn to g3 (g2·6)
c9-23455naming 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.
An opening trap from this Chess960 starting position.
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 1250 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.
Early Chess960 traps punish natural but careless development. Look for a forcing move that exploits a piece the opponent has just placed on a poor square — a fork, a pin or a threat that wins material before either side is fully developed.
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 a1, rook b1 f1, bishop h1, knight c1 e3, pawn a2 c2 d2 e2 f2 g2 b4 h4.
Black: king e8, queen a8, rook f4 b8, bishop g8 h8, knight d6 d8, pawn b6 a7 c7 d7 e7 g7 h7.
15 white and 15 black pieces are on the board; the puzzle position arises after move 6.
The position in numbers
Black are ahead by 2 points of material (36 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 6, with 29 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.
Black hold the bishop pair, an edge in open lines. The White king has 2 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
6. g3 Re4 7. d3 N8f7 8. dxe4
Why it works
- Great move! pawn to g3 keeps the pressure (+2.2).
- Well found: pawn to d3 (+2.2).
- Strong! pawn to e4 is the sharp choice (+2.9).
- You win a piece — the rook.
- If instead Re4, then d3 and you stay on top.
Move by move
- 6. g3 — pawn to g3
- Re4 — rook to e4
- 7. d3 — pawn to d3
- N8f7 — knight to f7
- 8. dxe4 — pawn to e4 (capture)
Types in this puzzle
Discovered attack
A piece steps aside and opens a second attack from the piece behind it.
A discovered attack works like a curtain: one piece steps off the line and unveils the long-range piece behind it. The beauty is that the moving piece can create a second threat of its own — two attacks in one move. Look for your stacked pairs: a bishop or rook behind a knight or pawn, aimed through them at something valuable. Send the front piece to the most aggressive square — a discovery without a second threat wastes half its power.
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.
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 #399.
SP-399 · ThroneGuard — Both knights start on inner files (b–g) while the king sits centrally on d or e — one of 204 positions filed here.
The king starts on e1, the rooks on b1 and f1, the queen on a1.
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: c2.
The setup belongs to the ThroneGuard family; read right to left it becomes position 752.
The engine's main line opens with b4.
Morozov Balance Index: 3 of 100 — class D — largest edge. Engine evaluation of the starting position: +65 centipawns for White (depth 44, 400 000 000 nodes).
In 50 self-play games White scored 52.0% (95% CI 38.5–65.2%).
Explore position #399Provenance
Mined from the project's engine self-play games.
Pack 009 · SP-399
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