Starting position #721
Back-rank setup: BRKBNQNR
SP-721 · BastionGuard — The king starts one file off-centre, on c or f, with neither knight in a corner.
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 h1, the queen on f1.
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.
One second-rank pawn starts with no defender at all: a2.
The setup belongs to the BastionGuard family; read right to left it becomes position 427.
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 20 Morozov Balance Index: 20 of 100 — class D — largest edge.
- Engine evaluation of the starting position: +37 centipawns for White (depth 45, 400 000 000 nodes).
- Rank 766 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): +40 → +1 → 0
Position facts
- Mirror twin: position #427
- The king starts on c, the rooks on b and h
- King and rook are neighbours — castling from adjacent squares feels unusual
- It becomes the daily position in 593 days
Puzzles from this position
- Attack on the uncastled king: bishop to a7 (d4·2) — Chess960 specifics · 780
- Winning blow: queen to d7 — Chess960 specifics · 920
- Attack on the uncastled king: king to b2 (c1·13) — Chess960 specifics · 970
- Winning blow: queen to a8 (a3·4) — Chess960 specifics · 1200
- Winning blow: rook to c7 (c8·4) — Chess960 specifics · 1280
- Winning blow: queen to c2 (e2) — Chess960 specifics · 1290
- Mate in 3: rook to g7 (h7) — Chess960 specifics · 1630
- Mate in 3: rook to d7 (d4) — Chess960 specifics · 1760
- Winning blow: queen to c6 (a4·4) — Chess960 specifics · 1870
- Winning blow: queen to b7 (b3·7) — Chess960 specifics · 2100
This position appears in course day 175
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Commentary
The king already stands on c1, so long castling moves the rook alone from b1. A bishop is closed into the corner on a1 with a single diagonal to h8; the second bishop is on d1. The pawn on a2 has no defender, and d2 leans on the king alone. The queen is on f1, the knights on e1 and g1, the second rook in the corner on h1. White's edge here is a wide one, +37 centipawns, and the queen recaptures on the fifth half-move: e4 e5 f4 exf4 Qxf4 Ne7.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.