Starting position #891
Back-rank setup: RQKRBNNB
SP-891 · BastionGuard — King shifted to c or f, knights kept clear of the edges — 168 positions in all.
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 d1, the queen on b1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
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 65.
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 2 Morozov Balance Index: 2 of 100 — class D — largest edge.
- Engine evaluation of the starting position: +53 centipawns for White (depth 41, 400 000 000 nodes).
- Rank 938 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 (56 half-moves): +43 → +9 → 0
Position facts
- Mirror twin: position #65
- The king starts on c, the rooks on a and d
- King and rook are neighbours — castling from adjacent squares feels unusual
- It becomes the daily position in 111 days
Puzzles from this position
- Attack on the uncastled king: pawn to f4 (g3·23) — Chess960 specifics · 780
- Attack on the uncastled king: queen to c3 (e1) — Chess960 specifics · 780
- Attack on the uncastled king: queen to h8 (b2·3) — Chess960 specifics · 920
- Winning blow: knight to f7 (g5·5) — Chess960 specifics · 1150
- Attack on the uncastled king: rook to a5 (a1·9) — Chess960 specifics · 1200
- Mate in 2: knight to d7 (c5) — Chess960 specifics · 1220
- Winning blow: rook to a5 (b5) — Chess960 specifics · 1420
- Mate in 2: queen to d8 (d5·7) — Chess960 specifics · 1450
- Mate in 3: queen to a8 (a2) — Chess960 specifics · 1760
- Winning blow: bishop to b6 (c5·5) — Chess960 specifics · 1980
This position appears in course day 71
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Commentary
The king already stands on c1, so long castling moves the rook alone; the rooks are on a1 and d1. A bishop holds the corner on h1 with one diagonal to a8; the second bishop is on e1. Every pawn on the second rank begins with a defender — this setup concedes nothing on move one. The queen stands on b1, right beside the king, and the knights are on f1 and g1. White's edge here is a wide one, +53 centipawns, and the line runs move for move in mirror: g3 g6 e4 e5 Ne3 Ne6.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.