Starting position #748
Back-rank setup: RBKNNQBR
SP-748 · 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 c1, the rooks on a1 and h1, the queen on f1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
The bishops stand on b1 and g1; their long diagonals reach h7 and a7 once the c- and f-pawns step aside.
The pawn on d2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the BastionGuard family; read right to left it becomes position 412.
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 14 Morozov Balance Index: 14 of 100 — class D — largest edge.
- Engine evaluation of the starting position: +42 centipawns for White (depth 45, 400 000 000 nodes).
- Rank 820 of 960 by balance — 1 is the most balanced start.
- In 50 self-play games White scored 55.0% (95% CI 41.3–67.9%).
- Balance band L — large edge · dynamics along the play-out: stable
- Evaluation along the engine's main line (58 half-moves): +39 → +28 → 0
Position facts
- Mirror twin: position #412
- The king starts on c, the rooks on a and h
- It becomes the daily position in 321 days
Puzzles from this position
- Winning blow: king to b2 (c1·2) — Chess960 specifics · 780
- Winning blow: knight to d7 (e5·2) — Chess960 specifics · 920
- Winning blow: pawn to b5 (a4·4) — Chess960 specifics · 920
- Attack on the uncastled king: rook to g2 (g4) — Chess960 specifics · 1010
- Winning blow: queen to e6 (b6·3) — Chess960 specifics · 1060
- Mate in 2: bishop to f4 (g5) — Chess960 specifics · 1090
- Winning blow: pawn to c4 (c3·2) — Chess960 specifics · 1110
- Mate in 2: queen to a7 (a5·2) — Chess960 specifics · 1320
- Mate in 3: pawn to d4 — Chess960 specifics · 1630
- Attack on the uncastled king: queen to c6 (c4) — Chess960 specifics · 2060
This position appears in course day 45
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Commentary
The king already stands on c1, so long castling moves the rook alone from a1. The bishops are on b1 and g1, the knights side by side on d1 and e1. Among the pawns, d2 leans on the king alone; no other second-rank pawn starts short of a defender. The queen is on f1, the second rook in the corner on h1. White's edge here is a wide one, +42 centipawns: e4 c6 a4 e5 a5 Ne6.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.