Starting position #496
Back-rank setup: BBRQNKNR
SP-496 · BastionGuard — Both knights begin inside the board while the king stands on c or f; a position and its mirror twin share this family.
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 c1 and h1, the queen on d1.
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.
The pawn on f2 is defended by the king alone — the classic soft spot of the standard setup.
The setup belongs to the BastionGuard family; read right to left it becomes position 559.
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 72 Morozov Balance Index: 72 of 100 — class B — balanced.
- Engine evaluation of the starting position: +20 centipawns for White (depth 48, 400 000 000 nodes).
- Rank 263 of 960 by balance — 1 is the most balanced start.
- Balance band S — slight edge · dynamics along the play-out: equalizing
- Evaluation along the engine's main line (60 half-moves): +23 → +30 → +7 → 0
Position facts
- Mirror twin: position #559
- The king starts on f, the rooks on c and h
- It becomes the daily position in 918 days
Puzzles from this position
- Attack on the uncastled king: rook to a7 — Chess960 specifics · 780
- Attack on the uncastled king: pawn to d5 (c4·98) — Chess960 specifics · 780
- Winning blow: rook to c8 (c1) — Chess960 specifics · 920
- Attack on the uncastled king: queen to d4 (d1·8) — Chess960 specifics · 1110
- Winning blow: king to c2 (c1·12) — Chess960 specifics · 1250
- Mate in 2: rook to c8 (c6) — Chess960 specifics · 1320
- Winning blow: queen to h6 (d2·5) — Chess960 specifics · 1470
- Attack on the uncastled king: queen to a8 (a7·2) — Chess960 specifics · 1630
- Mate in 3: queen to d5 (b3·3) — Chess960 specifics · 1980
- Mate in 3: queen to g6 (d3·3) — Chess960 specifics · 2170
This position appears in course day 64
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Commentary
Castling is ordinary in both directions from f1, with the rooks on c1 and h1. A bishop is shut into the corner on a1 with a single diagonal to h8; the second works the light squares from b1. Among the pawns, f2 leans on the king alone; no other second-rank pawn starts short of a defender. The queen is on d1, the knights on e1 and g1. The main line of the run opens c4 c5, then e4 b6 b3 e6.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.