Attack on the uncastled king: queen to c5 (g1·3)
c9-18507naming 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 1200 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 b1, queen g1, rook a1 h1, bishop c6, knight f1, pawn b2 c2 a3 g3 f4 h4 e5.
Black: king b8, queen g8, rook a8 h8, bishop c5, knight b5, pawn a4 f5 e6 h6 b7 g7.
13 white and 12 black pieces are on the board; the puzzle position arises after move 17.
The position in numbers
White are ahead by 1 points of material (32 against 31; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b1, the black king on b8.
It is White to move on move 17, with 29 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 6. Files fully open (no pawns of either colour): d — natural highways for the rooks and queen.
The White king has 3 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
17. Qxc5 bxc6 18. Qb6+ Kc8 19. O-O-O Nc7 20. Qxc6
Why it works
- Great move! queen to c5 keeps the pressure (+4.4).
- Spot on — queen to b6 (+4.4).
- A natural move: king to c1.
- Best move. queen to c6 is exactly what the engine plays (+4.6).
- You reach a winning position (+4.6).
- If instead bxc6, then Qb6+ and you stay on top.
Move by move
- 17. Qxc5 — queen to c5 (capture)
- bxc6 — pawn to c6 (capture)
- 18. Qb6+ — queen to b6 with check
- Kc8 — king to c8
- 19. O-O-O — king to a1
- Nc7 — knight to c7
- 20. Qxc6 — queen to c6 (capture)
Types in this puzzle
Zwischenzug
Before the obvious recapture — an in-between move that wins more.
A zwischenzug means refusing the obvious reply — usually a recapture — and playing a stronger move with tempo first. Typically it is a check or a deadly threat the opponent must answer, after which you calmly take what was hanging anyway. The sign: inside a sequence of exchanges you own a check or a threat that will not run away. Whenever a line looks forced, ask what poison you can slip in between the moves.
Counter-strike
Don't defend — answer the threat with a bigger one.
The counter-strike: instead of defending against the threat, you answer with a bigger threat of your own. While your opponent grabs a pawn, you deliver mate — the arithmetic favors you. Look for a counter when direct defenses fail: do you have a check, an attack on the queen, a mating threat? The beginner's error is meeting every threat with a reflexive defense without checking the counterattacking resources first.
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 #745.
SP-745 · RampartGuard — The king starts out on a wing file, b or g, with neither knight in a corner.
The king starts on b1, the rooks on a1 and h1, the queen on g1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
The bishops stand on d1 and e1; their long diagonals reach h5 and a5 once the e- and d-pawns step aside.
The pawn on b2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the RampartGuard family; read right to left it becomes position 409.
The engine's main line opens with a4.
Morozov Balance Index: 91 of 100 — class A — most balanced. Engine evaluation of the starting position: +13 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 #745Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-745
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