Attack on the uncastled king: rook to g3 (h3·4)
c9-25098naming 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 g1, queen e1, rook c1 h3, bishop a1 c4, knight d1, pawn a2 c2 f2 b4 h4.
Black: king g8, queen f7, rook f6 c8, bishop g2 f8, knight e6, pawn h5 b6 a7 c7 e7 g7.
12 white and 13 black pieces are on the board; the puzzle position arises after move 13.
The position in numbers
Black are ahead by 1 points of material (33 against 34; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on g1, the black king on g8.
It is White to move on move 13, with 42 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 6. Files fully open (no pawns of either colour): d — natural highways for the rooks and queen. Half-open for White: e, g.
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
13. Rg3 b5 14. Bb3 c5 15. bxc5 Rxc5 16. Rxg2
Why it works
- Great move! rook to g3 keeps the pressure (+4.5).
- Well found: bishop to b3 (+4.6).
- Strong! pawn to c5 is the sharp choice (+4.7).
- Best move. rook to g2 is exactly what the engine plays (+4.7).
- You win a piece — the bishop.
- If instead b5, then Bb3 and you stay on top.
Move by move
- 13. Rg3 — rook to g3
- b5 — pawn to b5
- 14. Bb3 — bishop to b3
- c5 — pawn to c5
- 15. bxc5 — pawn to c5 (capture)
- Rxc5 — rook to c5 (capture)
- 16. Rxg2 — rook to g2 (capture)
Types in this puzzle
Relative pin
A piece shields a more valuable one behind it — moving it loses material.
In a relative pin the piece shields not its king but something valuable behind it, usually the queen. Moving is legal but costly, because the piece behind falls. Look for three units on one line: your long-range piece, a cheaper enemy piece, and an expensive one hiding behind. Beware the classic trap — a relatively pinned piece can still move with check or a bigger threat, so verify before you cash in.
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.
Quiet move
No check, no capture — yet this modest move decides the game.
A quiet move gives no check and takes nothing — yet it decides the game by creating an unstoppable threat or stealing the king's last square. This is the hardest class of moves: the eye hunts for loud blows while a modest shift does the winning. The clue: every forcing try runs into a defense, so seek the move that strengthens the threat or takes squares away. Train yourself to ask: what if I neither capture nor check, but quietly improve?
About this position
These pieces come from starting position #146.
SP-146 · RampartGuard — A b- or g-file king and two knights on inner files (b–g).
The king starts on g1, the rooks on c1 and h1, the queen on e1.
The king already stands on its castled square, so castling short moves only the rook, from h1 to f1.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
One second-rank pawn starts with no defender at all: a2.
The setup belongs to the RampartGuard family; read right to left it becomes position 807.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 18 of 100 — class D — largest edge. Engine evaluation of the starting position: +38 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #146Provenance
Mined from the project's engine self-play games.
Pack 010 · SP-146
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