Castling-960 to the rescue on b1 (c1·8)
c9-25323naming 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 1480 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.
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 g1, rook b1, bishop e3 f5, knight g3, pawn a2 b2 e2 h2 c3 f3 g4.
Black: king b8, queen d5, rook b7 c7, bishop e8, knight a4 g6, pawn c4 e5 g5 f6.
13 white and 11 black pieces are on the board; the puzzle position arises after move 21.
The position in numbers
Black are ahead by 2 points of material (30 against 32; 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 b8.
It is White to move on move 21, with 34 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 4. Files fully open (no pawns of either colour): d — natural highways for the rooks and queen.
White hold the bishop pair, an edge in open lines. 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
21. O-O-O Ne7 22. Rxd5
Why it works
- Great move! king to c1 keeps the pressure (+1.8).
- A brilliant blow: rook to d5, and you stand better (+1.6).
- You win a piece — the queen.
- If instead Ne7, then Rxd5 and you win the queen.
Move by move
- 21. O-O-O — king to b1
- Ne7 — knight to e7
- 22. Rxd5 — rook to d5 (capture)
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.
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 #345.
SP-345 · BastionScout — Off-centre king plus a rim knight (a/h): 168 positions carry this shape.
The king starts on c1, the rooks on b1 and g1, the queen on f1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
The bishops stand on d1 and e1; their long diagonals reach h5 and a5 once the e- and d-pawns step aside.
The second rank carries 2 pawns with no defender at all: a2, h2.
The setup belongs to the BastionScout family; read right to left it becomes position 329.
The engine's main line opens with g4.
Morozov Balance Index: 47 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +27 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #345Provenance
Mined from the project's engine self-play games.
Pack 011 · SP-345
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