Castling-960 to the rescue on e1 (b1·2)
c9-19063naming 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 b1, queen e3, rook a1 e1, bishop c2, pawn b2 e2 g2 c3 d4 h4 a6.
Black: king b8, queen d7, rook a8, bishop g8, knight f7 f8, pawn b5 d5 f5 h5 a7 c7 h7.
12 white and 13 black pieces are on the board; the puzzle position arises after move 16.
The position in numbers
Black are ahead by 1 points of material (29 against 30; 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 b8.
It is White to move on move 16, with 40 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 7. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: f.
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
16. O-O Nd6 17. Bxf5 Nxf5 18. Rxf5
Why it works
- Great move! king to g1 keeps the pressure (+1.3).
- Well found: bishop to f5 (+1.6).
- Stunning! rook to f5 gives up material but you stand better (+1.4).
- You reach a winning position (+1.4).
- If instead Nd6, then Bxf5 and you stay on top.
Move by move
- 16. O-O — king to e1
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.
960 castling G-side
Chess960 castling to the G-side — king and rook leap to g1 and f1 from unusual squares.
Castling in Chess960 looks unusual: wherever the king and rook start, G-side castling lands them on the classical destination squares — king to g1, rook to f1. Sometimes the king travels half the board; sometimes it "castles in place." The conditions are the familiar ones: neither piece has moved, the path is clear, and the king never crosses an attacked square. In the app the gesture is simple — drag your king onto the rook.
About this position
These pieces come from starting position #909.
SP-909 · RampartScout — Wing king plus a rim knight, and only 72 positions qualify — the rarest pattern of all.
The king starts on b1, the rooks on a1 and e1, the queen on c1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
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 RampartScout family; read right to left it becomes position 56.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 34 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +31 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #909Provenance
Mined from the project's engine self-play games.
Pack 011 · SP-909
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