Starting position #209
Back-rank setup: BNQBRKNR
SP-209 · BastionGuard — Off-centre king (c/f), no knight on the a- or h-file.
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 e1 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.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
One second-rank pawn starts with no defender at all: a2.
The setup belongs to the BastionGuard family; read right to left it becomes position 651.
The engine's main line opens with b4.
Every sentence here is computed from the setup itself and can be checked on the board.
Balance
MBI 91 Morozov Balance Index: 91 of 100 — class A — most balanced.
- Engine evaluation of the starting position: +13 centipawns for White (depth 44, 400 000 000 nodes).
- Rank 97 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): +24 → -7 → 0 → 0
- Deeper check (1 200 000 000 nodes, depth 46): +16 cp, +3 cp against the base run — verified
Position facts
- Mirror twin: position #651
- The king starts on f, the rooks on e and h
- King and rook are neighbours — castling from adjacent squares feels unusual
- It becomes the daily position in 311 days
Puzzles from this position
- Attack on the uncastled king: king to f2 (g2) — Chess960 specifics · 780
- Attack on the uncastled king: queen to f4 (c1·6) — Chess960 specifics · 780
- Attack on the uncastled king: knight to e5 (c4·3) — Chess960 specifics · 920
- Attack on the uncastled king: queen to b1 (d1) — Chess960 specifics · 920
- Winning blow: queen to f7 (d5) — Chess960 specifics · 1010
- Attack on the uncastled king: rook to b3 (h3) — Chess960 specifics · 1200
- Attack on the uncastled king: rook to f7 (f4) — Chess960 specifics · 1320
- Winning blow: rook to g7 (g3·8) — Chess960 specifics · 1430
- Attack on the uncastled king: knight to g6 (e5·10) — Chess960 specifics · 1450
- Winning blow: rook to a1 (c1·4) — Chess960 specifics · 2060
This position appears in course day 37
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Commentary
Three second-rank squares are exposed: a2 with no defender at all, f2 and g2 with only the king. Castling is ordinary in both directions from f1. The corner bishop on a1 opens to h8 once the b-pawn moves; the second bishop is on d1. The queen stands on c1, the knights on b1 and g1. The engine's line opens b4 b5, then Nf3 Nf6 d3, and Black castles: O-O.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.