Starting position #553
Back-rank setup: RNKBBNQR
SP-553 · 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 c1, the rooks on a1 and h1, the queen on g1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
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 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 505.
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 72 Morozov Balance Index: 72 of 100 — class B — balanced.
- Engine evaluation of the starting position: +20 centipawns for White (depth 43, 400 000 000 nodes).
- Rank 261 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 (60 half-moves): +27 → +12 → 0
Position facts
- Mirror twin: position #505
- The king starts on c, the rooks on a and h
- It becomes the daily position in 1077 days
Puzzles from this position
- Attack on the uncastled king: queen to d4 — Chess960 specifics · 780
- Attack on the uncastled king: pawn to c4 (b3·15) — Chess960 specifics · 780
- Winning blow: queen to e2 — Chess960 specifics · 970
- Attack on the uncastled king: queen to f4 (h2) — Chess960 specifics · 1150
- Winning blow: queen to d4 (d8·2) — Chess960 specifics · 1280
- Mate in 2: queen to c8 (c5·5) — Chess960 specifics · 1450
- Winning blow: knight to c6 (e5·26) — Chess960 specifics · 1560
- Mate in 3: queen to a6 (a5) — Chess960 specifics · 1630
- Mate in 3: knight to b5 (d6) — Chess960 specifics · 1630
- Winning blow: rook to d3 (c3·4) — Chess960 specifics · 2290
This position appears in course day 51
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Commentary
The king already stands on c1, so long castling moves the rook alone from a1. The bishops stand side by side on d1 and e1, one on each colour. The pawn on b2 leans on the king alone; no other second-rank pawn starts short of a defender. The queen is on g1, the knights on b1 and f1. The engine takes the centre with e4 and both sides mirror: e4 e5 Nc3 Nc6 a4 a5.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.