Attack on the uncastled king: bishop to b6 (c5)
c9-10285naming 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 1290 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 b4, rook d2, bishop c5, knight e5, pawn a2 c2 e2 h2 g3 c4 f4.
Black: king d8, queen e8, rook c8 h8, bishop d6 g8, pawn f5 b6 a7 e7 g7 h7.
12 white and 12 black pieces are on the board; the puzzle position arises after move 17.
The position in numbers
Black are ahead by 4 points of material (27 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 c1, the black king on d8.
It is White to move on move 17, with 38 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. Half-open for White: b.
Black hold the bishop pair, an edge in open lines. 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. Bxb6+ Rc7 18. Rxd6+ Kc8 19. Bxc7
Why it works
- Great move! bishop to b6 keeps the pressure (#8).
- Well found: rook to d6 (#7).
- Strong! bishop to c7 is the sharp choice (#6).
- You win a piece — the rook.
- If instead Rc7, then Rxd6+ and you win the bishop.
Move by move
- 17. Bxb6+ — bishop to b6 (capture) with check
- Rc7 — rook to c7
- 18. Rxd6+ — rook to d6 (capture) with check
- Kc8 — king to c8
- 19. Bxc7 — bishop to c7 (capture)
Types in this puzzle
Win the pinned piece
The pinned piece cannot run — attack it again and win it.
A pinned piece cannot flee, which means you can win it outright by attacking it one more time. Count attackers against defenders: if you outnumber them, the piece is yours. The best extra attacker is a pawn, since it costs less than anything it might capture. Do not rush the capture — build up the pressure first, then harvest.
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.
Remove the defender
Capture the guard first — then take what it protected.
Removing the defender is the straightforward plan: capture the guard first, then take what it guarded. Unlike deflection, the defender is not lured away — it is traded off or destroyed on the spot. Stare at the target you crave and ask who defends it, and whether that defender can be profitably eaten. Count the whole capture sequence, not just the first move — the trade must pay off at the end.
About this position
These pieces come from starting position #268.
SP-268 · ThroneScout — A knight starts on the edge (a/h) and the king sits centrally on d or e; the mirror twin stays in this family too.
The king starts on d1, the rooks on c1 and h1, the queen on f1.
Castling long simply swaps the two pieces: the king on d1 and the rook on c1 trade places.
The bishops stand on b1 and g1; their long diagonals reach h7 and a7 once the c- and f-pawns step aside.
One second-rank pawn starts with no defender at all: b2.
The setup belongs to the ThroneScout family; read right to left it becomes position 604.
The engine's main line opens with c4.
Morozov Balance Index: 1 of 100 — class D — largest edge. Engine evaluation of the starting position: +58 centipawns for White (depth 43, 400 000 000 nodes).
In 50 self-play games White scored 58.0% (95% CI 44.2–70.6%).
Explore position #268Provenance
Mined from the project's engine self-play games.
Pack 009 · SP-268
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