Castling-960 to the rescue on a1 (c1·10)
c9-08843naming tag (square·N)Opens in the app if installed, otherwise downloads the APK.
The tactical motive
Castling 960: the strongest move is to castle — drag the king onto its rook.
Chess960 twist: use the unusual starting setup of the pieces.
Difficulty 1470 ShuffleRating — club-player level.
White to move — find the best continuation
How to recognize this tactic
Chess960 castling still ends with king and rook on the classical squares (g1/f1 or c1/d1), but the path can be unusual. Watch which squares the king crosses and whether castling here opens a file, drops a defender or walks into a 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.
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 f5, rook a1, bishop g1, knight h1 c5, pawn g2 h2 c3 f3 a4 e5.
Black: king c7, queen d5, rook b8, bishop f8, knight c4 g6, pawn a6 f6 g7 h7.
12 white and 10 black pieces are on the board; the puzzle position arises after move 20.
The position in numbers
White are ahead by 2 points of material (29 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 c1, the black king on c7.
It is White to move on move 20, with 39 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 4. Files fully open (no pawns of either colour): b, d — natural highways for the rooks and queen.
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
20. O-O-O Qxd1+ 21. Kxd1 Bxc5 22. Bxc5
Why it works
- Great move! king to c1 keeps the pressure (+4.7).
- Spot on — king to d1 (+5.0).
- Strong! bishop to c5 is the sharp choice (+5.0).
- You win a piece — the queen.
- If instead Qxd1+, then Kxd1 and you win the queen.
Move by move
- 20. O-O-O — king to a1
Types in this puzzle
Castling to safety
One move — castling — whisks the king out of mortal danger.
Castling to safety: the only escape from the attack is to castle — one move whisks the king to g1 or c1 and brings the rook into play as a bonus. In Chess960 this leap can cross half the board, which is exactly why it slips out of sight. Whenever your king is under pressure, ask first: can I still castle? The typical blunder is throwing that right away with a careless king or rook move.
Winning blow
Find the strike that wins material by force.
A winning blow is a forced material gain that does not fit a single textbook motif. The general tactical recipe applies: spot loose pieces, an awkwardly placed king, overloaded lines. Go through the forcing moves in order of violence — checks, captures, threats — because most combinations start with one of them. Do not judge by feel: calculate the concrete line until the outcome is beyond doubt.
Mate defense
Mate is threatened — parry it and stay on top.
Mate defense: your opponent is one move from mating you — but it is your turn, and that changes everything. Find the defense that kills the mating threat while keeping your advantage: often a check or a counter-threat that leaves no time for the mate. First name the exact square where the mate would land — otherwise you are defending blind. The mistake is playing a "defensive" move that does not actually remove the threat.
About this position
These pieces come from starting position #894.
SP-894 · BastionScout — King off-centre on c or f with a knight starting on the rim (a/h).
The king starts on c1, the rooks on a1 and d1, the queen on b1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
The bishops stand on f1 and g1; their long diagonals reach a6 and a7 once the e- and f-pawns step aside.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the BastionScout family; read right to left it becomes position 68.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 51 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +26 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #894Provenance
Mined from the project's engine self-play games.
Pack 011 · SP-894
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