Attack on the uncastled king: rook to c3 (a3·3)
c9-22391naming 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 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.
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 c1, queen b1, rook g1 a3, bishop e1, knight d2 e2, pawn b2 c2 f2 h2 e3 g3 a4 d4.
Black: king c8, queen c7, rook a8 g8, bishop f7 h8, knight e6 f8, pawn g4 d5 f5 a7 b7 e7 h7.
15 white and 15 black pieces are on the board; the puzzle position arises after move 11.
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 c1, the black king on c8.
It is White to move on move 11, with 28 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 1 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
11. Rc3 Ng6 12. Qa2 O-O 13. Rxc7
Why it works
- Great move! rook to c3 keeps the pressure (+3.0).
- Spot on — queen to a2 (+2.9).
- Strong! rook to c7 is the sharp choice (+3.0).
- You win a piece — the queen.
- If instead Ng6, then Qa2 and you stay on top.
Move by move
- 11. Rc3 — rook to c3
- Ng6 — knight to g6
- 12. Qa2 — queen to a2
- O-O — king to g8
- 13. Rxc7 — rook to c7 (capture)
Types in this puzzle
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.
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 #699.
SP-699 · BastionGuard — King shifted to c or f, knights kept clear of the edges — 168 positions in all.
The king starts on c1, the rooks on a1 and g1, the queen on b1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
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: e2.
The setup belongs to the BastionGuard family; read right to left it becomes position 449.
The engine's main line opens with c3.
Morozov Balance Index: 4 of 100 — class D — largest edge. Engine evaluation of the starting position: +50 centipawns for White (depth 41, 400 000 000 nodes).
Explore position #699Provenance
Mined from the project's engine self-play games.
Pack 009 · SP-699
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