Starting position #505
Back-rank setup: RQNBBKNR
SP-505 · 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 a1 and h1, the queen on b1.
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 e1; their long diagonals reach h5 and a5 once the e- 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 553.
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 51 Morozov Balance Index: 51 of 100 — class B — balanced.
- Engine evaluation of the starting position: +26 centipawns for White (depth 43, 400 000 000 nodes).
- Rank 473 of 960 by balance — 1 is the most balanced start.
- Balance band M — moderate edge · dynamics along the play-out: sharpening
- Evaluation along the engine's main line (60 half-moves): +28 → +16 → +25 → +21
Position facts
- Mirror twin: position #553
- The king starts on f, the rooks on a and h
- It becomes the daily position in 207 days
Puzzles from this position
- Attack on the uncastled king: pawn to b5 — Chess960 specifics · 780
- Attack on the uncastled king: queen to f4 (e4·2) — Chess960 specifics · 780
- Attack on the uncastled king: pawn to f6 (e5·17) — Chess960 specifics · 780
- Attack on the uncastled king: queen to e4 (b1·9) — Chess960 specifics · 780
- Winning blow: queen to g6 (h5·2) — Chess960 specifics · 920
- Winning blow: rook to f1 (f2·3) — Chess960 specifics · 1200
- Mate in 2: queen to e5 (d5) — Chess960 specifics · 1220
- Mate in 2: queen to d8 (b6·3) — Chess960 specifics · 1320
- Mate in 3: bishop to b4 — Chess960 specifics · 1630
- Winning blow: queen to h6 (d2·6) — Chess960 specifics · 1870
This position appears in course day 8
In your browser or in the Android app. Nothing to install · Free, no ads
Commentary
Castling is ordinary in both directions from f1, with the rooks in the corners on a1 and h1. The bishops stand side by side on d1 and e1, one on each colour. The pawn on g2 leans on the king alone; no other second-rank pawn starts short of a defender. The queen is on b1, the knights on c1 and g1. The engine takes the centre with d4 and the line runs d4 Nf6 c4 d6 a4 e5.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.