Starting position #745
Back-rank setup: RKNBBNQR
SP-745 · RampartGuard — The king starts out on a wing file, b or g, 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 b1, the rooks on a1 and h1, the queen on g1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
The bishops stand on d1 and e1; their long diagonals reach h5 and a5 once the e- and d-pawns step aside.
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 409.
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 91 Morozov Balance Index: 91 of 100 — class A — most balanced.
- Engine evaluation of the starting position: +13 centipawns for White (depth 44, 400 000 000 nodes).
- Rank 85 of 960 by balance — 1 is the most balanced start.
- In 50 self-play games White scored 52.0% (95% CI 38.5–65.2%).
- Balance band S — slight edge · dynamics along the play-out: equalizing
- Evaluation along the engine's main line (70 half-moves): +22 → -3 → 0 → -4 → 0
- Deeper check (1 200 000 000 nodes, depth 48): +23 cp, +10 cp against the base run — verified
Position facts
- Mirror twin: position #409
- The king starts on b, the rooks on a and h
- King and rook are neighbours — castling from adjacent squares feels unusual
- It becomes the daily position in 599 days
Puzzles from this position
- Attack on the uncastled king: king to b2 (b1·4) — Chess960 specifics · 780
- Winning blow: queen to a6 (a7) — Chess960 specifics · 920
- Winning blow: queen to a5 (c3·2) — Chess960 specifics · 1150
- Winning blow: bishop to d7 (a4·2) — Chess960 specifics · 1200
- Winning blow: rook to e5 (e3·3) — Chess960 specifics · 1290
- Attack on the uncastled king: knight to a6 (b4) — Chess960 specifics · 1320
- Winning blow: queen to a7 (c5·7) — Chess960 specifics · 1560
- Mate in 3: queen to a8 (c6·3) — Chess960 specifics · 1630
- Mate in 3: rook to a7 (a8·3) — Chess960 specifics · 1760
- Chess960 tactic on b7 (e4·2) — Chess960 specifics · 2400
This position appears in course day 20
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Commentary
The king begins on b1, and short castling takes him five squares across the board to g1. The bishops stand side by side on d1 and e1, one on each colour. The pawn on b2 leans on the king alone; no other second-rank pawn starts short of a defender. The queen is on g1, the knights on c1 and f1, the rooks in the corners on a1 and h1. The engine keeps the edge small, +13 centipawns, and both sides mirror: a4 a5 d4 d5 f3 f6.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.