Starting position #433
Back-rank setup: BRNBNQKR
SP-433 · RampartGuard — The king starts out on a wing file, b or g, with neither knight in a corner.
Move the pieces right on the board — full Chess960 rules, castle by dropping the king on the rook.
Position features
The king starts on g1, the rooks on b1 and h1, the queen on f1.
The king already stands on its castled square, so castling short moves only the rook, from h1 to f1.
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: d2.
The setup belongs to the RampartGuard family; read right to left it becomes position 715.
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 99 Morozov Balance Index: 99 of 100 — class A — most balanced.
- Engine evaluation of the starting position: -4 centipawns for White (depth 41, 400 000 000 nodes).
- Rank 13 of 960 by balance — 1 is the most balanced start.
- In 50 self-play games White scored 53.0% (95% CI 39.5–66.1%).
- Balance band E — even · dynamics along the play-out: stable
- Evaluation along the engine's main line (47 half-moves): +31 → +15 → 0
- Deeper check (4 000 000 000 nodes, depth 53): +3 cp, +7 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 51.5% (95% CI 41.8–61.1%)
Position facts
- Mirror twin: position #715
- The king starts on g, the rooks on b and h
- King and rook are neighbours — castling from adjacent squares feels unusual
- It becomes the daily position in 5 days
Puzzles from this position
- Attack on the uncastled king: king to f2 (g1·4) — Chess960 specifics · 780
- Attack on the uncastled king: rook to c5 (c1·2) — Chess960 specifics · 780
- Attack on the uncastled king: pawn to c5 (d4·27) — Chess960 specifics · 780
- Attack on the uncastled king: knight to f8 (e6) — Chess960 specifics · 780
- Attack on the uncastled king: knight to d7 (c5·16) — Chess960 specifics · 920
- Winning blow: king to h2 (g1·8) — Chess960 specifics · 970
- Winning blow: pawn to c7 (c6·10) — Chess960 specifics · 1250
- Mate in 3: queen to d6 (e5) — Chess960 specifics · 1630
- Winning blow: bishop to f6 (d4·6) — Chess960 specifics · 1870
- Winning blow: queen to e8 (c6·6) — Chess960 specifics · 2290
This position appears in course day 94
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Commentary
The engine's number lands on Black's side here: -4 centipawns at depth 41, a hair either way. The king starts on g1, already on the square short castling would give him, so that castling moves the rook alone. A bishop is closed into the corner on a1 with a single diagonal to h8; the second bishop is on d1. Among the pawns, d2 is the one that begins without a defender. The queen is on f1 beside her king, and the line runs e4 c5 Bf3 e6 Qe2 Ne7.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.