Starting position #517
Back-rank setup: RNBBQKNR
SP-517 · 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 e1.
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 c1 and d1; their long diagonals reach h6 and h5 once the d- and e-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 538.
The engine's main line opens with e4, 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 89 Morozov Balance Index: 89 of 100 — class A — most balanced.
- Engine evaluation of the starting position: +14 centipawns for White (depth 47, 400 000 000 nodes).
- Rank 106 of 960 by balance — 1 is the most balanced start.
- Balance band S — slight edge · dynamics along the play-out: stable
- Evaluation along the engine's main line (70 half-moves): +27 → +9 → -7 → 0
- Deeper check (1 200 000 000 nodes, depth 53): +15 cp, +1 cp against the base run — verified
Position facts
- Mirror twin: position #538
- The king starts on f, the rooks on a and h
- It becomes the daily position in 1222 days
Puzzles from this position
- Attack on the uncastled king: knight to c7 (b5·4) — Chess960 specifics · 780
- Attack on the uncastled king: knight to g5 (e4) — Chess960 specifics · 780
- Winning blow: pawn to d5 (e4) — Chess960 specifics · 780
- Attack on the uncastled king: pawn to d5 (e4·60) — Chess960 specifics · 780
- Attack on the uncastled king: pawn to a4 (b3·14) — Chess960 specifics · 780
- Winning blow: knight to e4 (c3·3) — Chess960 specifics · 780
- Winning blow: king to h1 (g1·9) — Chess960 specifics · 970
- Attack on the uncastled king: pawn to c4 (d3·39) — Chess960 specifics · 1200
- Mate in 2: rook to h8 (h7·5) — Chess960 specifics · 1320
- Chess960 tactic on e8 (c8) — Chess960 specifics · 2250
This position appears in course day 38
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Commentary
Castling is ordinary in both directions from f1, with the queen on e1 next to her king. The bishops stand side by side on c1 and d1, one on each colour. The pawn on g2 leans on the king alone; no other second-rank pawn starts short of a defender. The rooks sit in the corners, a1 and h1, the knights on b1 and g1. The engine takes the centre with e4 and castles on the fifth half-move: e4 e5 Ne2 Ne7 O-O d5.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.