Starting position #539
Back-rank setup: RNKQBNRB
SP-539 · 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 c1, the rooks on a1 and g1, the queen on d1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
The pawn on b2 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 513.
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 37 Morozov Balance Index: 37 of 100 — class C — noticeable edge.
- Engine evaluation of the starting position: +30 centipawns for White (depth 42, 400 000 000 nodes).
- Rank 602 of 960 by balance — 1 is the most balanced start.
- Balance band M — moderate edge · dynamics along the play-out: equalizing
- Evaluation along the engine's main line (60 half-moves): +43 → +39 → +3 → 0
Position facts
- Mirror twin: position #513
- The king starts on c, the rooks on a and g
- It becomes the daily position in 723 days
Puzzles from this position
- Attack on the uncastled king: pawn to a3 (b2·9) — Chess960 specifics · 780
- Attack on the uncastled king: pawn to c4 (b3·30) — Chess960 specifics · 780
- Winning blow: king to c2 (c1·7) — Chess960 specifics · 970
- Winning blow: knight to f1 (e3) — Chess960 specifics · 1110
- Attack on the uncastled king: pawn to f6 (g5·19) — Chess960 specifics · 1280
- Mate in 2: rook to a7 (b7·3) — Chess960 specifics · 1320
- Mate in 3: pawn to f4 — Chess960 specifics · 1630
- Attack on the uncastled king: rook to a8 (a1·10) — Chess960 specifics · 1630
- Winning blow: knight to b5 (a3·3) — Chess960 specifics · 2240
- Chess960 tactic on e4 (e2) — Chess960 specifics · 2400
This position appears in course day 124
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Commentary
The king already stands on c1, so long castling moves the rook alone from a1. A bishop holds the corner on h1 with one diagonal to a8; the second bishop is on e1. Among the pawns, b2 leans on the king alone; no other second-rank pawn starts short of a defender. The queen is on d1 beside her king, the knights on b1 and f1. The engine takes the centre with e4 and the centre trades off at once: e4 e6 d4 d5 exd5 exd5.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.