Starting position #155
Back-rank setup: NRNQBKRB
SP-155 · BastionScout — King shifted to c or f, with a knight committed to the corner from move one.
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 d1.
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 BastionScout family; read right to left it becomes position 801.
The engine's main line opens with c4.
Every sentence here is computed from the setup itself and can be checked on the board.
Balance
MBI 89 Morozov Balance Index: 89 of 100 — class A — most balanced.
- Engine evaluation of the starting position: +14 centipawns for White (depth 46, 400 000 000 nodes).
- Rank 114 of 960 by balance — 1 is the most balanced start.
- Balance band S — slight edge · dynamics along the play-out: stable
- Evaluation along the engine's main line (45 half-moves): +29 → 0 → 0
- Deeper check (1 200 000 000 nodes, depth 50): +18 cp, +4 cp against the base run — verified
Position facts
- Mirror twin: position #801
- 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: bishop to d6 (f4) — Chess960 specifics · 780
- Attack on the uncastled king: pawn to f5 (e4·27) — Chess960 specifics · 780
- Attack on the uncastled king: pawn to d5 (c4·84) — Chess960 specifics · 780
- Winning blow: rook to c7 (c2) — Chess960 specifics · 920
- Attack on the uncastled king: bishop to b7 (h1·11) — Chess960 specifics · 920
- Winning blow: pawn to h4 (h2) — Chess960 specifics · 1250
- Winning blow: queen to d4 (d1·4) — Chess960 specifics · 1390
- Mate in 3: king to f1 — Chess960 specifics · 1630
- Winning blow: bishop to h5 (f3·5) — Chess960 specifics · 1700
- Chess960 tactic on g7 (g4·3) — Chess960 specifics · 2400
This position appears in course day 63
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Commentary
Short castling swaps the king on f1 with the rook on g1. A knight is in the corner on a1 with a single move, b3, and a bishop in the corner on h1 with one diagonal to a8. Among the pawns, h2 begins with no defender at all. The queen stands on d1, the second bishop on e1. The engine's line opens c4 c5, then both sides castle at once — O-O O-O — before d3 d6.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.