Starting position #504
Back-rank setup: RBQNBKNR
SP-504 · BastionGuard — King off-centre on c or f with both knights on inner files.
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 a1 and h1, the queen on c1.
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 b1 and e1; their long diagonals reach h7 and a5 once the c- and d-pawns step aside.
The pawn on g2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the BastionGuard family; read right to left it becomes position 557.
The engine's main line opens with d4, putting a pawn straight into the centre.
Every sentence here is computed from the setup itself and can be checked on the board.
Balance
MBI 8 Morozov Balance Index: 8 of 100 — class D — largest edge.
- Engine evaluation of the starting position: +45 centipawns for White (depth 45, 400 000 000 nodes).
- Rank 881 of 960 by balance — 1 is the most balanced start.
- Balance band L — large edge · dynamics along the play-out: stable
- Evaluation along the engine's main line (60 half-moves): +47 → +59 → +35 → +5
Position facts
- Mirror twin: position #557
- The king starts on f, the rooks on a and h
- This position does not come up as the daily position in the next four years
Puzzles from this position
- Winning blow: pawn to e5 (d4) — Chess960 specifics · 780
- Attack on the uncastled king: pawn to b5 (c4·15) — Chess960 specifics · 780
- Attack on the uncastled king: queen to a8 (c8) — Chess960 specifics · 780
- Attack on the uncastled king: knight to e5 (d3·16) — Chess960 specifics · 1060
- Winning blow: bishop to b1 (a2) — Chess960 specifics · 1200
- Winning blow: knight to f5 (e3·17) — Chess960 specifics · 1280
- Mate in 2: rook to g7 (g1·2) — Chess960 specifics · 1320
- Mate in 3: knight to g5 (f3) — Chess960 specifics · 1630
- Winning blow: queen to d5 (e4·2) — Chess960 specifics · 1790
- Chess960 tactic on d5 (g5) — Chess960 specifics · 2350
This position appears in course day 46
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Commentary
Castling is ordinary in both directions from f1, with the rooks in the corners on a1 and h1. The bishops are on b1 and e1, the knights on d1 and g1. The pawn on g2 leans on the king alone; no other second-rank pawn starts short of a defender. The queen is on c1. White's edge here is a wide one, +45 centipawns, and the d-pawn goes two squares up: d4 c5 d5 c4 e4 f5.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.