Starting position #109
Back-rank setup: QNRBNKBR
SP-109 · 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 c1 and h1, the queen on a1.
Castling ends where it always does: king to g1 and rook to f1 on the short side, king to c1 and rook to d1 on the long one.
The bishops stand on d1 and g1; their long diagonals reach h5 and a7 once the e- and f-pawns step aside.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the BastionGuard family; read right to left it becomes position 856.
The engine's main line opens with h3.
Every sentence here is computed from the setup itself and can be checked on the board.
Balance
MBI 94 Morozov Balance Index: 94 of 100 — class A — most balanced.
- Engine evaluation of the starting position: +10 centipawns for White (depth 49, 400 000 000 nodes).
- Rank 63 of 960 by balance — 1 is the most balanced start.
- Balance band E — even · dynamics along the play-out: equalizing
- Evaluation along the engine's main line (70 half-moves): +15 → 0 → 0 → 0
- Deeper check (1 200 000 000 nodes, depth 54): +9 cp, -1 cp against the base run — verified
Position facts
- Mirror twin: position #856
- The king starts on f, the rooks on c and h
- It becomes the daily position in 1332 days
Puzzles from this position
- Winning blow: knight to c8 — Chess960 specifics · 780
- Attack on the uncastled king: pawn to c4 (d3·4) — Chess960 specifics · 780
- Attack on the uncastled king: knight to d2 (b3) — Chess960 specifics · 780
- Attack on the uncastled king: knight to e4 (c3·14) — Chess960 specifics · 780
- Attack on the uncastled king: queen to a8 (a1·2) — Chess960 specifics · 920
- Winning blow: queen to e4 (f4) — Chess960 specifics · 1150
- Winning blow: knight to d5 (c3·14) — Chess960 specifics · 1250
- Mate in 3: rook to d7 (a7) — Chess960 specifics · 1630
- Attack on the uncastled king: queen to b8 (c8) — Chess960 specifics · 1870
- Chess960 tactic on f7 (h5) — Chess960 specifics · 2400
This position appears in course day 21
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Commentary
Castling is ordinary in both directions from f1, though the rooks begin far apart on c1 and h1. The queen is in the corner on a1, the bishops on d1 and g1. No pawn on the second rank starts without a defender. The knights are on b1 and e1. The published line opens h3, a quiet first move, and continues c5 Bh2 h6 c4 Bh7 — both bishops step out to the h-file.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.