Starting position #513
Back-rank setup: BRNBQKNR
SP-513 · BastionGuard — King shifted to c or f, knights kept clear of the edges — 168 positions in all.
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 b1 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.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
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 539.
The engine's main line opens with Nh3, bringing the knight out to h3.
Every sentence here is computed from the setup itself and can be checked on the board.
Balance
MBI 86 Morozov Balance Index: 86 of 100 — class A — most balanced.
- Engine evaluation of the starting position: +15 centipawns for White (depth 42, 400 000 000 nodes).
- Rank 133 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): +20 → -5 → 0 → -8
- Deeper check (1 200 000 000 nodes, depth 47): +21 cp, +6 cp against the base run — verified
Position facts
- Mirror twin: position #539
- The king starts on f, the rooks on b and h
- It becomes the daily position in 997 days
Puzzles from this position
- Attack on the uncastled king: pawn to f4 (g3·4) — Chess960 specifics · 780
- Attack on the uncastled king: pawn to c5 (b4·6) — Chess960 specifics · 780
- Winning blow: knight to b8 (d7) — Chess960 specifics · 780
- Winning blow: rook to f6 (d6) — Chess960 specifics · 920
- Winning blow: knight to g5 (e6) — Chess960 specifics · 920
- Winning blow: bishop to g7 (a1·4) — Chess960 specifics · 1060
- Attack on the uncastled king: bishop to e4 (f3·10) — Chess960 specifics · 1150
- Attack on the uncastled king: bishop to c4 (e2·8) — Chess960 specifics · 1280
- Mate in 3: rook to f7 (g7) — Chess960 specifics · 1630
- Mate in 3: queen to g7 (h6·3) — Chess960 specifics · 1990
This position appears in course day 28
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Commentary
The engine's first move here puts a knight on the rim: Nh3, and White castles two moves later — Nh3 b5 O-O c5 e4 e6. Castling is ordinary in both directions from f1, with the queen on e1 next to her king. A bishop is closed into the corner on a1 with a single diagonal to h8; the second bishop is on d1. On the second rank, g2 leans on the king alone; no other second-rank pawn starts short of a defender. The knights are on c1 and g1, the rooks on b1 and h1.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.