Starting position #502
Back-rank setup: RQBNKBNR
SP-502 · ThroneGuard — A centre-file king with no knight on the edge; a position and its mirror twin always share this family.
Move the pieces right on the board — full Chess960 rules, castle by dropping the king on the rook.
Position features
The king starts on e1, the rooks on a1 and h1, the queen on b1.
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.
The bishops stand on c1 and f1; their long diagonals reach h6 and a6 once the d- and e-pawns step aside.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the ThroneGuard family; read right to left it becomes position 550.
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 69 Morozov Balance Index: 69 of 100 — class B — balanced.
- Engine evaluation of the starting position: +21 centipawns for White (depth 48, 400 000 000 nodes).
- Rank 302 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): +37 → +29 → 0
Position facts
- Mirror twin: position #550
- The king starts on e, the rooks on a and h
- This position does not come up as the daily position in the next four years
Puzzles from this position
- Attack on the uncastled king: rook to a8 — Chess960 specifics · 780
- Attack on the uncastled king: bishop to f6 (b2·3) — Chess960 specifics · 780
- Attack on the uncastled king: pawn to b4 (a3·19) — Chess960 specifics · 780
- Attack on the uncastled king: queen to d6 (e5) — Chess960 specifics · 970
- Winning blow: rook to e6 (e1·12) — Chess960 specifics · 1200
- Winning blow: pawn to c6 (d5·5) — Chess960 specifics · 1200
- Castling-960 to the rescue on a1 (e1·2) — Castling-960 · 1340
- Winning blow: knight to f7 (e5·12) — Chess960 specifics · 1610
- Attack on the uncastled king: bishop to f4 (c1·36) — Chess960 specifics · 1750
- Attack on the uncastled king: queen to e6 (c4·3) — Chess960 specifics · 2120
This position appears in course day 52
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Commentary
Castling is ordinary in both directions from e1, with the rooks in the corners on a1 and h1. Every pawn on the second rank begins with a defender — this setup concedes nothing on move one. The bishops are on c1 and f1, the knights on d1 and g1. The queen is on b1. The engine takes the centre with e4 and the line runs e4 c5 c3 e6 Nf3 Nc6.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.