Starting position #557
Back-rank setup: RNKBNQBR
SP-557 · BastionGuard — Off-centre king (c/f), no knight on the a- or h-file.
Move the pieces right on the board — full Chess960 rules, castle by dropping the king on the rook.
Position features
The king starts on c1, the rooks on a1 and h1, the queen on f1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
The bishops stand on d1 and g1; their long diagonals reach h5 and a7 once the e- and f-pawns step aside.
The pawn on b2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the BastionGuard family; read right to left it becomes position 504.
The engine's main line opens with e4, putting a pawn straight into the centre.
Every sentence here is computed from the setup itself and can be checked on the board.
Balance
MBI 0 Morozov Balance Index: 0 of 100 — class D — largest edge.
- Engine evaluation of the starting position: +63 centipawns for White (depth 44, 400 000 000 nodes).
- Rank 960 of 960 by balance — 1 is the most balanced start.
- In 50 self-play games White scored 65.0% (95% CI 51.1–76.7%).
- Balance band L — large edge · dynamics along the play-out: volatile
- Evaluation along the engine's main line (60 half-moves): +75 → +61 → +24 → 0
Position facts
- Mirror twin: position #504
- The king starts on c, the rooks on a and h
- It becomes the daily position in 553 days
Puzzles from this position
- Attack on the uncastled king: pawn to c4 (d3·19) — Chess960 specifics · 780
- Winning blow: bishop to f2 (g1) — Chess960 specifics · 920
- Attack on the uncastled king: knight to d2 (b1) — Chess960 specifics · 970
- Attack on the uncastled king: knight to b6 (a4·4) — Chess960 specifics · 1060
- Attack on the uncastled king: pawn to e5 (e4·2) — Chess960 specifics · 1110
- Winning blow: rook to c1 (h1·5) — Chess960 specifics · 1200
- Winning blow: rook to e6 (e2·3) — Chess960 specifics · 1290
- Winning blow: knight to f7 (d6·5) — Chess960 specifics · 1420
- Winning blow: bishop to c5 (e3·3) — Chess960 specifics · 1560
- Winning blow: pawn to a8 (a7·8) — Chess960 specifics · 2060
This position appears in course day 92
In your browser or in the Android app. Nothing to install · Free, no ads
Commentary
White's edge here is unusually wide: +63 centipawns at depth 44. The king already stands on c1, so long castling moves the rook alone from a1. The bishops are on d1 and g1, the knights on b1 and e1. Among the pawns, b2 leans on the king alone; no other second-rank pawn starts short of a defender. The queen is on f1 and recaptures on the fifth half-move: e4 e5 f4 exf4 Qxf4 Nc6.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.