Starting position #35
Back-rank setup: BNNQRKRB
SP-35 · 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 f1, the rooks on e1 and g1, the queen on d1.
Castling short simply swaps the two pieces: the king on f1 and the rook on g1 trade places.
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: h2.
The setup belongs to the BastionGuard family; read right to left it becomes position 915.
The engine's main line opens with b3.
Every sentence here is computed from the setup itself and can be checked on the board.
Balance
MBI 97 Morozov Balance Index: 97 of 100 — class A — most balanced.
- Engine evaluation of the starting position: +6 centipawns for White (depth 45, 400 000 000 nodes).
- Rank 34 of 960 by balance — 1 is the most balanced start.
- Balance band E — even · dynamics along the play-out: equalizing
- Evaluation along the engine's main line (70 half-moves): +21 → +16 → 0 → 0
- Deeper check (1 200 000 000 nodes, depth 51): +11 cp, +5 cp against the base run — verified · S — slight edge
Position facts
- Mirror twin: position #915
- The king starts on f, the rooks on e and g
- King and rook are neighbours — castling from adjacent squares feels unusual
- It becomes the daily position in 60 days
Puzzles from this position
- Attack on the uncastled king: bishop to a8 (h1) — Chess960 specifics · 780
- Attack on the uncastled king: pawn to h4 (g3·4) — Chess960 specifics · 780
- Attack on the uncastled king: bishop to a8 (h1·15) — Chess960 specifics · 780
- Attack on the uncastled king: knight to e8 (d6·4) — Chess960 specifics · 780
- Attack on the uncastled king: bishop to e6 (g4·2) — Chess960 specifics · 920
- Winning blow: rook to d1 (c1·2) — Chess960 specifics · 1200
- Mate in 2: queen to c8 (c3·5) — Chess960 specifics · 1320
- Winning blow: queen to c2 (d2·6) — Chess960 specifics · 1610
- Mate in 3: queen to h6 (g5) — Chess960 specifics · 1980
- Chess960 tactic on h4 (g4) — Chess960 specifics · 2400
This position appears in course day 22
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Commentary
Short castling swaps the king on f1 with the rook on g1. Both corners hold a bishop: a1 on the dark squares with a diagonal to h8, h1 on the light ones with a diagonal to a8, each waiting on a single pawn move. The queen is on d1, the knights on b1 and c1. Among the pawns, h2 begins with no defender at all, and f2 has only the king. That combination — two corner bishops and two exposed pawns — is what the engine has to weigh here. Its main line opens b3 b6, then c4 c5 d4 g6.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.