Starting position #849
Back-rank setup: BRKBNRNQ
SP-849 · 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 b1 and f1, the queen on h1.
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 107.
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 80 Morozov Balance Index: 80 of 100 — class A — most balanced.
- Engine evaluation of the starting position: +17 centipawns for White (depth 45, 400 000 000 nodes).
- Rank 184 of 960 by balance — 1 is the most balanced start.
- Balance band S — slight edge · dynamics along the play-out: equalizing
- Evaluation along the engine's main line (50 half-moves): +43 → +24 → 0
Position facts
- Mirror twin: position #107
- The king starts on c, the rooks on b and f
- King and rook are neighbours — castling from adjacent squares feels unusual
- It becomes the daily position in 617 days
Puzzles from this position
- Winning blow: pawn to d3 (c2·6) — Chess960 specifics · 780
- Attack on the uncastled king: knight to f8 (g6·2) — Chess960 specifics · 780
- Winning blow: queen to a5 (a6·2) — Chess960 specifics · 970
- Winning blow: king to d1 (c1·13) — Chess960 specifics · 1110
- Attack on the uncastled king: queen to e4 (h1·9) — Chess960 specifics · 1150
- Attack on the uncastled king: queen to a6 (c6·2) — Chess960 specifics · 1200
- Mate in 2: queen to d7 (h3) — Chess960 specifics · 1320
- Castling-960 to the rescue on f1 (c1) — Castling-960 · 1340
- Mate in 3: rook to a1 (b1) — Chess960 specifics · 1630
- Winning blow: rook to f8 (f2·4) — Chess960 specifics · 2060
This position appears in course day 167
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Commentary
The king already stands on c1 and the rook already occupies f1, so each castling sends a single piece — the rook one way, the king the other. The queen begins in the corner on h1, and a bishop holds the opposite corner on a1 with its one diagonal to h8; the second bishop is on d1. On the second rank, a2 begins without a defender, and the pawn on d2 leans on the king alone. The knights are on e1 and g1 — both can reach f3, so a knight move there has to name its file, and the second rook is on b1. White's edge is a narrow +17 centipawns: e4 e5 f4 exf4 Nd3 Ne7.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.