Starting position #497
Back-rank setup: BRQBNKNR
SP-497 · 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 f1, the rooks on b1 and h1, the queen on c1.
Castling ends where it always does: king to g1 and rook to f1 on the short side, king to c1 and rook to d1 on the long one.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
One second-rank pawn starts with no defender at all: a2.
The setup belongs to the BastionGuard family; read right to left it becomes position 555.
The engine's main line opens with c4.
Every sentence here is computed from the setup itself and can be checked on the board.
Balance
MBI 98 Morozov Balance Index: 98 of 100 — class A — most balanced.
- Engine evaluation of the starting position: 0 centipawns for White (depth 46, 400 000 000 nodes).
- Rank 17 of 960 by balance — 1 is the most balanced start.
- In 50 self-play games White scored 48.0% (95% CI 34.8–61.5%).
- Balance band E — even · dynamics along the play-out: equalizing
- Evaluation along the engine's main line (70 half-moves): +18 → 0 → 0 → 0
- Deeper check (4 000 000 000 nodes, depth 53): +6 cp, +6 cp against the base run — verified
- Sign verdict: even — within engine noise
- Self-play v2: 100 games at 1 000 000 nodes per move — White scored 49.0% (95% CI 39.4–58.7%)
Position facts
- Mirror twin: position #555
- The king starts on f, the rooks on b and h
- It becomes the daily position in 282 days
Puzzles from this position
- Attack on the uncastled king: pawn to d5 (c4·10) — Chess960 specifics · 780
- Attack on the uncastled king: pawn to d3 (e2·2) — Chess960 specifics · 780
- Attack on the uncastled king: queen to c5 (c1·2) — Chess960 specifics · 780
- Attack on the uncastled king: pawn to b6 (c5·19) — Chess960 specifics · 780
- Winning blow: rook to g5 (d5·2) — Chess960 specifics · 1010
- Attack on the uncastled king: queen to b8 (b2·3) — Chess960 specifics · 1110
- Attack on the uncastled king: bishop to a4 (d1·14) — Chess960 specifics · 1250
- Winning blow: rook to e1 (d1·7) — Chess960 specifics · 1390
- Mate in 2: rook to d7 (d6·5) — Chess960 specifics · 1630
- Attack on the uncastled king: queen to c8 (c7·2) — Chess960 specifics · 2400
This position appears in course day 43
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Commentary
The engine calls this one dead level: +0 centipawns after a search to depth 46. Castling is ordinary in both directions from f1, with the rooks on b1 and h1. A bishop is closed into the corner on a1 with a single diagonal to h8; the second bishop is on d1. Among the pawns, a2 has no defender, and f2 leans on the king alone. The queen is on c1, and both sides mirror each other for six half-moves: c4 c5 e3 e6 Ne2 Ne7.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.