Starting position #80
Back-rank setup: BBNNRKRQ
SP-80 · BastionGuard — A c- or f-file king and two knights on inner files (b–g).
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 e1 and g1, the queen on h1.
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 a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
One second-rank pawn starts with no defender at all: d2.
The setup belongs to the BastionGuard family; read right to left it becomes position 879.
The engine's main line opens with g4.
Every sentence here is computed from the setup itself and can be checked on the board.
Balance
MBI 1 Morozov Balance Index: 1 of 100 — class D — largest edge.
- Engine evaluation of the starting position: +83 centipawns for White (depth 43, 400 000 000 nodes).
- Rank 955 of 960 by balance — 1 is the most balanced start.
- In 50 self-play games White scored 56.0% (95% CI 42.3–68.8%).
- Balance band L — large edge · dynamics along the play-out: volatile
- Evaluation along the engine's main line (60 half-moves): +64 → +91 → +129 → +176
Position facts
- Mirror twin: position #879
- The king starts on f, the rooks on e and g
- King and rook are neighbours — castling from adjacent squares feels unusual
- It becomes the daily position in 875 days
Puzzles from this position
- Attack on the uncastled king: knight to d7 (e5) — Chess960 specifics · 620
- Attack on the uncastled king: bishop to d3 (b1·2) — Chess960 specifics · 780
- Winning blow: bishop to d4 (c3) — Chess960 specifics · 920
- Winning blow: queen to f3 (h1·2) — Chess960 specifics · 1060
- Attack on the uncastled king: rook to h1 (g1·18) — Chess960 specifics · 1250
- Winning blow: knight to b6 (d5·11) — Chess960 specifics · 1510
- Attack on the uncastled king: knight to g6 (f4·12) — Chess960 specifics · 1650
- Winning blow: queen to e7 (d8·5) — Chess960 specifics · 1870
- Winning blow: bishop to c4 (d3·11) — Chess960 specifics · 2060
- Chess960 tactic on g6 (g4·2) — Chess960 specifics · 2400
This position appears in course day 12
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Commentary
The queen begins in the corner on h1, the furthest square from the centre on her side of the board. Short castling swaps the king on f1 with the rook on g1. A bishop is shut into the corner on a1 and waits for the b-pawn before its diagonal to h8 opens; the second works the light squares from b1. On the second rank, d2 begins with no defender. The recorded line opens g4, a wide first move, and continues Nd6 b3 a6 Nd3 Ne6.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.