Starting position #427
Back-rank setup: RNQNBKRB
SP-427 · BastionGuard — The king starts one file off-centre, on c or f, with neither knight in a corner.
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 c1.
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.
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 721.
The engine's main line opens with d3.
Every sentence here is computed from the setup itself and can be checked on the board.
Balance
MBI 40 Morozov Balance Index: 40 of 100 — class C — noticeable edge.
- Engine evaluation of the starting position: +29 centipawns for White (depth 43, 400 000 000 nodes).
- Rank 574 of 960 by balance — 1 is the most balanced start.
- Balance band M — moderate edge · dynamics along the play-out: stable
- Evaluation along the engine's main line (60 half-moves): +41 → +27 → 0
Position facts
- Mirror twin: position #721
- 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 510 days
Puzzles from this position
- Attack on the uncastled king: bishop to c6 (d5) — Chess960 specifics · 780
- Attack on the uncastled king: pawn to a4 (b3·9) — Chess960 specifics · 780
- Attack on the uncastled king: queen to c8 (c1·4) — Chess960 specifics · 920
- Winning blow: queen to h6 (h4·2) — Chess960 specifics · 1010
- Attack on the uncastled king: queen to d2 (e2) — Chess960 specifics · 1200
- Winning blow: queen to g8 (e6·3) — Chess960 specifics · 1280
- Attack on the uncastled king: queen to g8 (g3·4) — Chess960 specifics · 1320
- Castling-960 to the rescue on a8 (f8) — Castling-960 · 1340
- Mate in 3: queen to h8 (g7·3) — Chess960 specifics · 1630
- Attack on the uncastled king: bishop to c6 (h1·17) — Chess960 specifics · 2150
This position appears in course day 44
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Commentary
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. The pawn on h2 has no defender, and e2 leans on the king alone. The queen is on c1, the knights on b1 and d1, the second rook in the corner on a1. The published line opens d3 d5, then g3 Bc6 d4 O-O, with Black castling on the sixth half-move.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.