Starting position #103
Back-rank setup: QNBRNKRB
SP-103 · BastionGuard — The king starts one file off-centre, on c or f, 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 f1, the rooks on d1 and g1, the queen on a1.
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 BastionGuard family; read right to left it becomes position 850.
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 80 Morozov Balance Index: 80 of 100 — class A — most balanced.
- Engine evaluation of the starting position: +17 centipawns for White (depth 48, 400 000 000 nodes).
- Rank 205 of 960 by balance — 1 is the most balanced start.
- Balance band S — slight edge · dynamics along the play-out: equalizing
- Evaluation along the engine's main line (60 half-moves): +43 → +20 → 0
Position facts
- Mirror twin: position #850
- The king starts on f, the rooks on d 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 g3 (f2) — Chess960 specifics · 780
- Attack on the uncastled king: pawn to g3 (h2·17) — Chess960 specifics · 780
- Winning blow: knight to d6 (f5·2) — Chess960 specifics · 920
- Winning blow: queen to e5 (e4·4) — Chess960 specifics · 1010
- Winning blow: queen to e6 (g6·2) — Chess960 specifics · 1200
- Winning blow: queen to g7 (g5·2) — Chess960 specifics · 1290
- Mate in 2: queen to g8 (g6·2) — Chess960 specifics · 1320
- Attack on the uncastled king: bishop to a3 (c1·3) — Chess960 specifics · 1630
- Mate in 2: queen to h7 (g6·2) — Chess960 specifics · 1670
- Chess960 tactic on d7 (d1·5) — Chess960 specifics · 2350
This position appears in course day 104
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Commentary
Short castling swaps the king on f1 with the rook on g1; long castling moves the king alone, since the rook already occupies d1. The queen is in the corner on a1, a bishop in the corner on h1 with a single diagonal to a8. Three second-rank squares are exposed: h2 has no defender at all, and e2 and f2 have only the king. The second bishop stands on c1, the knights on b1 and e1. The published line opens c4 c6, then b3 g6 Bb2 Bxb2 — the long diagonal is traded off at once.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.