Starting position #898
Back-rank setup: BRKQRBNN
SP-898 · 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 b1 and e1, the queen on d1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
The second rank carries 2 pawns with no defender at all: a2, h2.
The setup belongs to the BastionScout family; read right to left it becomes position 55.
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 51 Morozov Balance Index: 51 of 100 — class C — noticeable edge.
- Engine evaluation of the starting position: +26 centipawns for White (depth 45, 400 000 000 nodes).
- Rank 450 of 960 by balance — 1 is the most balanced start.
- Balance band M — moderate edge · dynamics along the play-out: equalizing
- Evaluation along the engine's main line (60 half-moves): +54 → 0 → +6 → 0
Position facts
- Mirror twin: position #55
- The king starts on c, the rooks on b and e
- King and rook are neighbours — castling from adjacent squares feels unusual
- It becomes the daily position in 304 days
Puzzles from this position
- Winning blow: king to b1 — Chess960 specifics · 780
- Winning blow: queen to b2 (c2) — Chess960 specifics · 1010
- Winning blow: queen to a5 (c3) — Chess960 specifics · 1110
- Winning blow: knight to e5 (f3·13) — Chess960 specifics · 1200
- Winning blow: queen to d8 (e7·2) — Chess960 specifics · 1280
- Winning blow: pawn to c7 (d6·7) — Chess960 specifics · 1280
- Winning blow: queen to d6 (d5·5) — Chess960 specifics · 1510
- Attack on the uncastled king: pawn to b7 (b6·6) — Chess960 specifics · 1700
- Mate in 3: rook to e8 (e1·11) — Chess960 specifics · 1860
- Chess960 tactic on b6 (d4·2) — Chess960 specifics · 2350
This position appears in course day 140
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Commentary
The queen keeps her classical square d1, but the king stands to her left, on c1, so long castling moves the rook alone. A bishop holds the corner on a1 with one diagonal to h8; the second bishop is on f1. Two pawns begin without a defender, a2 and h2 — the edges of the rank. The knights are on g1 and h1 — the cornered one has g3 as its only move, and the rooks are on b1 and e1. White's edge is +26 centipawns: f4 e6 e4 f5 b4 fxe4.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.