Starting position #803
Back-rank setup: BRKQNRNB
SP-803 · BastionGuard — Off-centre king (c/f), no knight on the a- or h-file.
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 f1, 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 BastionGuard family; read right to left it becomes position 147.
The engine's main line opens with g3.
Every sentence here is computed from the setup itself and can be checked on the board.
Balance
MBI 34 Morozov Balance Index: 34 of 100 — class C — noticeable edge.
- Engine evaluation of the starting position: +31 centipawns for White (depth 48, 400 000 000 nodes).
- Rank 626 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): +45 → +4 → 0
Position facts
- Mirror twin: position #147
- The king starts on c, the rooks on b and f
- King and rook are neighbours — castling from adjacent squares feels unusual
- This position does not come up as the daily position in the next four years
Puzzles from this position
- Attack on the uncastled king: pawn to c4 (b3·9) — Chess960 specifics · 780
- Winning blow: knight to c6 (d4) — Chess960 specifics · 780
- Attack on the uncastled king: pawn to g5 (f4·36) — Chess960 specifics · 920
- Winning blow: knight to a5 (c6·3) — Chess960 specifics · 1060
- Winning blow: rook to f6 (f1·8) — Chess960 specifics · 1280
- Mate in 2: queen to a5 (c5) — Chess960 specifics · 1320
- Winning blow: queen to e6 (e7·3) — Chess960 specifics · 1610
- Mate in 3: rook to g8 (g1·2) — Chess960 specifics · 1630
- Mate in 3: queen to b6 (b3·2) — Chess960 specifics · 1860
- Mate in 3: queen to b6 (f2·3) — Chess960 specifics · 2170
This position appears in course day 49
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Commentary
Both bishops start in the corners, on a1 and h1, each with a single long diagonal — one to h8, the other to a8. 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. Two pawns begin without a defender, a2 and h2 — the edges of the rank. The knights are on e1 and g1 — both can reach f3, so a knight move there has to name its file. White's edge is +31 centipawns, and the engine opens on the flank with g3: g3 g6 d4 Nd6 b3 f5.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.