Starting position #419
Back-rank setup: BRNQNKRB
SP-419 · 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 b1 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 723.
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 89 Morozov Balance Index: 89 of 100 — class A — most balanced.
- Engine evaluation of the starting position: +14 centipawns for White (depth 47, 400 000 000 nodes).
- Rank 109 of 960 by balance — 1 is the most balanced start.
- Balance band S — slight edge · dynamics along the play-out: stable
- Evaluation along the engine's main line (70 half-moves): +24 → +26 → +10 → 0
- Deeper check (1 200 000 000 nodes, depth 54): +29 cp, +15 cp against the base run — not confirmed at depth · M — moderate edge
Position facts
- Mirror twin: position #723
- The king starts on f, the rooks on b and g
- King and rook are neighbours — castling from adjacent squares feels unusual
- It becomes the daily position in 227 days
Puzzles from this position
- Attack on the uncastled king: knight to d7 (e5·2) — Chess960 specifics · 620
- Attack on the uncastled king: pawn to d5 (c4·24) — Chess960 specifics · 780
- Attack on the uncastled king: queen to a8 (f3·2) — Chess960 specifics · 780
- Attack on the uncastled king: pawn to a4 (b3·13) — Chess960 specifics · 780
- Winning blow: knight to e7 (d5·3) — Chess960 specifics · 920
- Winning blow: knight to f3 (e1) — Chess960 specifics · 970
- Winning blow: queen to e5 (e2·2) — Chess960 specifics · 1250
- Mate in 3: queen to e4 (e7) — Chess960 specifics · 1630
- Mate in 3: queen to h7 (h4·5) — Chess960 specifics · 1860
- Winning blow: queen to f7 (c7·3) — Chess960 specifics · 2350
This position appears in course day 7
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Commentary
Both corners hold a bishop, a1 towards h8 and h1 towards a8, each with a single diagonal. In the engine's line the second one is traded off in place: after b3 b6 g3 comes Bxh1, and White takes back in the corner: Rxh1 g6. Short castling swaps the king on f1 with the rook on g1. Among the pawns, h2 has no defender, and f2 leans on the king alone. The queen is on d1, the knights on c1 and e1.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.