Starting position #655
Back-rank setup: RNKRQNBB
SP-655 · 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 d1, the queen on e1.
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, c2 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 208.
The engine's main line opens with f4.
Every sentence here is computed from the setup itself and can be checked on the board.
Balance
MBI 51 Morozov Balance Index: 51 of 100 — class B — balanced.
- Engine evaluation of the starting position: +26 centipawns for White (depth 45, 400 000 000 nodes).
- Rank 465 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): +22 → +42 → +21 → 0
Position facts
- Mirror twin: position #208
- The king starts on c, the rooks on a and d
- King and rook are neighbours — castling from adjacent squares feels unusual
- This position does not come up as the daily position in the next four years
Puzzles from this position
- Attack on the uncastled king: pawn to c3 (b2·9) — Chess960 specifics · 780
- Winning blow: queen to e8 (b5) — Chess960 specifics · 780
- Winning blow: pawn to e5 (f4·13) — Chess960 specifics · 920
- Attack on the uncastled king: rook to a2 (a1·10) — Chess960 specifics · 1060
- Winning blow: rook to d4 (d2) — Chess960 specifics · 1150
- Attack on the uncastled king: knight to b6 (d5·3) — Chess960 specifics · 1290
- Mate in 3: pawn to a4 — Chess960 specifics · 1630
- Mate in 3: queen to g8 (g5·2) — Chess960 specifics · 1860
- Winning blow: rook to a7 (a1·12) — Chess960 specifics · 2100
- Chess960 tactic on e8 (g8·2) — Chess960 specifics · 2250
This position appears in course day 32
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Commentary
The king already stands on c1, so long castling moves the rook alone from d1. A bishop holds the corner on h1 with one diagonal to a8; the second bishop is on g1. Two second-rank pawns lean on the king alone: b2 and c2, side by side. The queen is on e1, the knights on b1 and f1, the second rook in the corner on a1. The published line opens f4 f5, then d4 d5 g4 g6.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.