Starting position #731
Back-rank setup: RKNQBNRB
SP-731 · RampartGuard — A wing king (b/g) with 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 b1, the rooks on a1 and g1, the queen on d1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
The pawn on b2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the RampartGuard family; read right to left it becomes position 417.
The engine's main line opens with a4.
Every sentence here is computed from the setup itself and can be checked on the board.
Balance
MBI 34 Morozov Balance Index: 34 of 100 — class C — noticeable edge.
- Engine evaluation of the starting position: +31 centipawns for White (depth 46, 400 000 000 nodes).
- Rank 631 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): +45 → +22 → +10 → +15
Position facts
- Mirror twin: position #417
- The king starts on b, the rooks on a and g
- King and rook are neighbours — castling from adjacent squares feels unusual
- This position does not come up as the daily position in the next four years
Puzzles from this position
- Attack on the uncastled king: rook to h1 — Chess960 specifics · 780
- Attack on the uncastled king: pawn to d3 (c2·9) — Chess960 specifics · 780
- Attack on the uncastled king: knight to c6 (d4·5) — Chess960 specifics · 920
- Attack on the uncastled king: queen to c4 (b3·3) — Chess960 specifics · 1060
- Attack on the uncastled king: knight to c4 (d2·11) — Chess960 specifics · 1200
- Winning blow: bishop to c6 (h1·5) — Chess960 specifics · 1280
- Mate in 2: rook to h7 (g7) — Chess960 specifics · 1320
- Attack on the uncastled king: bishop to e4 (h1·12) — Chess960 specifics · 1340
- Castling-960 to the rescue on g1 (b1) — Castling-960 · 1760
- Chess960 tactic on c7 (b5) — Chess960 specifics · 2400
This position appears in course day 100
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Commentary
The king begins on b1, and short castling takes him five squares across the board to g1. A bishop holds the corner on h1 with one diagonal to a8; the second bishop is on e1. Among the pawns, b2 leans on the king alone; no other second-rank pawn starts short of a defender. The queen is on d1, the knights on c1 and f1, the second rook in the corner on a1. The engine's first move is the a-pawn, and both sides mirror: a4 a5 g3 g6 d4 d5.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.