Starting position #443
Back-rank setup: RNNQBKRB
SP-443 · 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 a1 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 h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
The second rank carries 2 pawns with no defender at all: b2, h2.
The setup belongs to the BastionGuard family; read right to left it becomes position 705.
The engine's main line opens with c4.
Every sentence here is computed from the setup itself and can be checked on the board.
Balance
MBI 98 Morozov Balance Index: 98 of 100 — class A — most balanced.
- Engine evaluation of the starting position: +5 centipawns for White (depth 47, 400 000 000 nodes).
- Rank 18 of 960 by balance — 1 is the most balanced start.
- Balance band E — even · dynamics along the play-out: stable
- Evaluation along the engine's main line (56 half-moves): +26 → +16 → 0
- Deeper check (1 200 000 000 nodes, depth 51): +11 cp, +6 cp against the base run — verified · S — slight edge
Position facts
- Mirror twin: position #705
- The king starts on f, the rooks on a and g
- King and rook are neighbours — castling from adjacent squares feels unusual
- It becomes the daily position in 106 days
Puzzles from this position
- Attack on the uncastled king: pawn to b5 (a4·2) — Chess960 specifics · 780
- Attack on the uncastled king: pawn to d6 (c5·7) — Chess960 specifics · 780
- Attack on the uncastled king: bishop to a5 (c3·3) — Chess960 specifics · 780
- Attack on the uncastled king: bishop to a5 (e1·11) — Chess960 specifics · 780
- Attack on the uncastled king: pawn to e5 (d4·88) — Chess960 specifics · 780
- Winning blow: pawn to g4 (f3·3) — Chess960 specifics · 920
- Winning blow: rook to f1 (e1·3) — Chess960 specifics · 1280
- Mate in 3: bishop to f4 (e5) — Chess960 specifics · 1630
- Mate in 3: knight to g8 (f6) — Chess960 specifics · 1760
- Attack on the uncastled king: queen to d8 (d3·4) — Chess960 specifics · 2400
This position appears in course day 44
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Commentary
The engine finds almost nothing for White here: +5 centipawns at depth 47. Short castling swaps the king on f1 with the rook on g1. A bishop holds the corner on h1 with one diagonal to a8; the second bishop is on e1. Two pawns begin with no defender at all: b2 and h2. The knights stand side by side on b1 and c1, the queen on d1, and the line runs c4 c5 g3 Nc6 d3 O-O.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.