Starting position #685
Back-rank setup: QRKBNNBR
SP-685 · 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 a1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
The bishops stand on d1 and g1; their long diagonals reach h5 and a7 once the e- and f-pawns step aside.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the BastionGuard family; read right to left it becomes position 472.
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 11 Morozov Balance Index: 11 of 100 — class D — largest edge.
- Engine evaluation of the starting position: +42 centipawns for White (depth 45, 400 000 000 nodes).
- Rank 853 of 960 by balance — 1 is the most balanced start.
- Balance band L — large edge · dynamics along the play-out: equalizing
- Evaluation along the engine's main line (40 half-moves): +45 → +8 → 0
Position facts
- Mirror twin: position #472
- The king starts on c, the rooks on b and h
- 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: queen to e8 (e5·2) — Chess960 specifics · 620
- Attack on the uncastled king: pawn to d4 (c3·18) — Chess960 specifics · 780
- Attack on the uncastled king: pawn to a6 (b5·8) — Chess960 specifics · 780
- Winning blow: queen to g8 (g7·2) — Chess960 specifics · 920
- Winning blow: queen to c3 (b2) — Chess960 specifics · 970
- Attack on the uncastled king: queen to c4 (b3·4) — Chess960 specifics · 1150
- Mate in 2: queen to d8 (d7·3) — Chess960 specifics · 1320
- Attack on the uncastled king: queen to d6 (a3·3) — Chess960 specifics · 1410
- Mate in 3: rook to f7 (f1·2) — Chess960 specifics · 1630
- Mate in 3: rook to a7 (a3) — Chess960 specifics · 1980
This position appears in course day 9
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Commentary
The king already stands on c1, so long castling moves the rook alone from b1. Every pawn on the second rank begins with a defender — this setup concedes nothing on move one. The bishops are on d1 and g1, the knights side by side on e1 and f1. The queen begins in the far corner on a1, the second rook in the corner on h1. White's edge here is a wide one, +42 centipawns: e4 b6 f3 a5 a4 e5.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.