Starting position #139
Back-rank setup: NRQNBKRB
SP-139 · BastionScout — A c- or f-file king with at least one knight out on the edge.
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 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.
The second rank carries 2 pawns with no defender at all: a2, h2.
The setup belongs to the BastionScout family; read right to left it becomes position 817.
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 43 Morozov Balance Index: 43 of 100 — class C — noticeable edge.
- Engine evaluation of the starting position: +28 centipawns for White (depth 48, 400 000 000 nodes).
- Rank 555 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): +25 → +6 → -11 → -6
Position facts
- Mirror twin: position #817
- The king starts on f, the rooks on b 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: pawn to c4 (b3·11) — Chess960 specifics · 780
- Winning blow: queen to b5 (a5) — Chess960 specifics · 780
- Attack on the uncastled king: knight to d4 (b3·19) — Chess960 specifics · 920
- Attack on the uncastled king: knight to c4 (e3·8) — Chess960 specifics · 920
- Winning blow: knight to e7 (d5·14) — Chess960 specifics · 920
- Attack on the uncastled king: rook to h1 (g1·15) — Chess960 specifics · 1110
- Winning blow: king to h2 (g1·29) — Chess960 specifics · 1250
- Winning blow: knight to d4 (f5·3) — Chess960 specifics · 1390
- Mate in 3: queen to c6 (c1) — Chess960 specifics · 1630
- Attack on the uncastled king: queen to e7 (e3·6) — Chess960 specifics · 1860
This position appears in course day 57
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Commentary
Short castling swaps the king on f1 with the rook on g1. A knight starts in the corner on a1 with b3 as its only move, a bishop in the corner on h1 with one diagonal to a8. The pawns on a2 and h2 have no defender at all, and e2 has only the king. The queen is on c1, the second bishop on e1. The published line opens d3, a modest first move, and continues b5 b4 d6 Nb3 Nb6.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.