Starting position #638
Back-rank setup: RNKQRBBN
SP-638 · BastionScout — The king starts one file off-centre, on c or f, and a knight begins 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 c1, the rooks on a1 and e1, the queen on d1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
The bishops stand on f1 and g1; their long diagonals reach a6 and a7 once the e- and f-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 BastionScout family; read right to left it becomes position 228.
The engine's main line opens with f4.
Every sentence here is computed from the setup itself and can be checked on the board.
Balance
MBI 28 Morozov Balance Index: 28 of 100 — class C — noticeable edge.
- Engine evaluation of the starting position: +33 centipawns for White (depth 43, 400 000 000 nodes).
- Rank 686 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): +33 → +20 → +8 → 0
Position facts
- Mirror twin: position #228
- The king starts on c, the rooks on a and e
- It becomes the daily position in 35 days
Puzzles from this position
- Attack on the uncastled king: queen to f4 — Chess960 specifics · 780
- Winning blow: knight to d4 (b5·2) — Chess960 specifics · 920
- Winning blow: queen to h5 (e8) — Chess960 specifics · 970
- Winning blow: queen to d6 (d2·3) — Chess960 specifics · 1010
- Attack on the uncastled king: king to a3 — Chess960 specifics · 1060
- Mate in 2: rook to d7 (d6·2) — Chess960 specifics · 1090
- Mate in 2: queen to c5 (f2·2) — Chess960 specifics · 1450
- Winning blow: bishop to d7 (b5·6) — Chess960 specifics · 1790
- Chess960 tactic on a6 (c5) — Chess960 specifics · 2120
- Chess960 tactic on c5 (c1·2) — Chess960 specifics · 2350
This position appears in course day 39
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Commentary
The king already stands on c1, so long castling moves the rook alone from a1. The bishops sit together on f1 and g1, the knights on b1 and h1 — the cornered one has g3 as its only move. On the second rank, b2 leans on the king alone; no other second-rank pawn starts short of a defender. The queen is on d1 beside her king, the second rook on e1. White's edge here is a wide one, +33 centipawns: f4 f6 e4 e5 Nc3 exf4.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.