Castling-960 to the rescue on a1 (b1·9)
c9-22012naming 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.
Winning tactic: there is a move that gains a decisive advantage — find it.
Difficulty 1760 ShuffleRating — for advanced tacticians.
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.
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, rook a1, pawn f2 h2 b3 g3 a4.
Black: king a8, bishop f1, knight f8, pawn c3 b7 c7 f7 g7 h7.
7 white and 9 black pieces are on the board; the puzzle position arises after move 24.
The position in numbers
Black are ahead by 2 points of material (10 against 12; 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 a8.
It is White to move on move 24, with 13 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, e — natural highways for the rooks and queen. Half-open for White: c.
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
24. O-O-O Ne6 25. Rxf1 Nd4 26. b4 Nc6 27. Kc2
Why it works
- Great move! king to c1 keeps the pressure (+3.9).
- Well found: rook to f1 (+4.0).
- A natural move: pawn to b4.
- Sensible development: king to c2.
- You win a piece — the bishop.
- If instead Ne6, then Rxf1 and you win the bishop.
Move by move
- 24. O-O-O — king to a1
- Ne6 — knight to e6
- 25. Rxf1 — rook to f1 (capture)
- Nd4 — knight to d4
- 26. b4 — pawn to b4
- Nc6 — knight to c6
- 27. Kc2 — king to c2
Types in this puzzle
960 castling C-side
Chess960 castling to the C-side — the king lands on c1 wherever it started.
C-side castling in Chess960 sends the king to c1 and the rook to d1, no matter where they began. Sometimes it is one small hop, sometimes a journey through the center — check in advance which squares must be empty and whether any of them are attacked. The rules match classical chess: neither piece has moved, and the king never passes through check. In the game, just drag the king onto the rook.
Only move
Everything else loses — find the only move that holds.
An only move is a position where everything loses except one single continuation. You cannot play "by hand" here: run through fundamentally different defenses — run away, block, trade, counterattack — and discard the ones that fail. The hallmark of these puzzles is that the obvious moves lose quickly while the solution often looks strange. First understand exactly what the threat is — then the one saving move reveals itself.
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.
About this position
These pieces come from starting position #922.
SP-922 · RampartScout — A knight in the corner and the king out on the wing (b/g); like every family, it is closed under mirror twins.
The king starts on b1, the rooks on a1 and c1, the queen on d1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
The bishops stand on e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the RampartScout family; read right to left it becomes position 37.
The engine's main line opens with c4.
Morozov Balance Index: 97 of 100 — class A — most balanced. Engine evaluation of the starting position: +7 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #922Provenance
Mined from the project's engine self-play games.
Pack 013 · SP-922
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