Starting position #904
Back-rank setup: RBKQBRNN
SP-904 · BastionScout — A knight on the a- or h-file, king on c or f — the mirror twin lands here as well.
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 f1, the queen on d1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
The bishops stand on b1 and e1; their long diagonals reach h7 and a5 once the c- and d-pawns step aside.
The second rank carries 2 pawns with no defender at all: g2, h2.
The setup belongs to the BastionScout family; read right to left it becomes position 61.
The engine's main line opens with f4.
Every sentence here is computed from the setup itself and can be checked on the board.
Balance
MBI 47 Morozov Balance Index: 47 of 100 — class C — noticeable edge.
- Engine evaluation of the starting position: +27 centipawns for White (depth 41, 400 000 000 nodes).
- Rank 494 of 960 by balance — 1 is the most balanced start.
- Balance band M — moderate edge · dynamics along the play-out: stable
- Evaluation along the engine's main line (60 half-moves): +29 → +23 → +19 → 0
Position facts
- Mirror twin: position #61
- The king starts on c, the rooks on a and f
- It becomes the daily position in 61 days
Puzzles from this position
- Winning blow: pawn to b7 — Chess960 specifics · 780
- Attack on the uncastled king: pawn to h5 — Chess960 specifics · 780
- Attack on the uncastled king: knight to h4 (f3·10) — Chess960 specifics · 780
- Attack on the uncastled king: knight to f5 (g3·11) — Chess960 specifics · 780
- Winning blow: king to b1 (c1·6) — Chess960 specifics · 970
- Winning blow: rook to b7 (b1·2) — Chess960 specifics · 1010
- Mate in 2: queen to d8 (d6·2) — Chess960 specifics · 1320
- Winning blow: queen to d2 (d4·2) — Chess960 specifics · 1430
- Mate in 2: bishop to d6 (b8) — Chess960 specifics · 1630
- Chess960 tactic on a8 (c6) — Chess960 specifics · 2120
This position appears in course day 2
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Commentary
The queen keeps her classical square d1, and the king stands on c1, so long castling moves the rook alone; the rook already occupies f1, which leaves short castling to the king alone. The bishops are on b1 and e1, one on each colour. Two pawns begin without a defender, g2 and h2, and the pawn on b2 leans on the king alone. The knights are on g1 and h1 — the cornered one has g3 as its only move, and the second rook is on a1. White's edge is +27 centipawns, and the engine opens on the flank with f4: f4 a5 Nf3 c5 e3 d5.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.