Attack on the uncastled king: bishop to a4 (c2·3)
c9-26536naming 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 f2, rook c1 d4, bishop c2, knight e3, pawn d2 e2 g2 f3 a5 h5.
Black: king e8, queen a7, rook b1 h8, bishop f7, pawn e6 f6 e7 g7 h7.
11 white and 10 black pieces are on the board; the puzzle position arises after move 20.
The position in numbers
Black are ahead by 5 points of material (22 against 27; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on f2, the black king on e8.
It is White to move on move 20, with 43 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 5. Files fully open (no pawns of either colour): b, c — natural highways for the rooks and queen.
The White king has 4 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
20. Ba4+ Kf8 21. Rc8+ Be8 22. Rxe8+ Kf7 23. Rxh8
Why it works
- Great move! bishop to a4 keeps the pressure (+4.5).
- Spot on — rook to c8 (+5.2).
- Strong! rook to e8 is the sharp choice (+5.2).
- Best move. rook to h8 is exactly what the engine plays (+5.3).
- You win a piece — the rook.
- If instead Kf8, then Rc8+ and you stay on top.
Move by move
- 20. Ba4+ — bishop to a4 with check
- Kf8 — king to f8
- 21. Rc8+ — rook to c8 with check
- Be8 — bishop to e8
- 22. Rxe8+ — rook to e8 (capture) with check
- Kf7 — king to f7
- 23. Rxh8 — rook to h8 (capture)
Types in this puzzle
Skewer
A line attack forces the valuable piece to move, exposing the one behind it.
A skewer is a pin turned inside out: the valuable piece stands in front and something cheaper hides behind it. The big piece must step aside, and you collect the one that was sheltering in its shadow. Scan for the enemy king or queen sharing a file, rank or diagonal with another enemy piece. The deadliest version comes with check — the king moves, the rook behind it dies.
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 #221.
SP-221 · ThroneScout — King in the middle of the rank, with a knight already committed to the corner.
The king starts on e1, the rooks on c1 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 d1 and g1; their long diagonals reach h5 and a7 once the e- and f-pawns step aside.
One second-rank pawn starts with no defender at all: g2.
The setup belongs to the ThroneScout family; read right to left it becomes position 648.
The engine's main line opens with c4.
Morozov Balance Index: 65 of 100 — class B — balanced. Engine evaluation of the starting position: +22 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #221Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-221
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