Starting position #258
Back-rank setup: BNRKNBQR
SP-258 · ThroneGuard — King on a central file (d/e) with both knights on inner files — the classic-type setup.
Move the pieces right on the board — full Chess960 rules, castle by dropping the king on the rook.
Position features
The king starts on d1, the rooks on c1 and h1, the queen on g1.
Castling long simply swaps the two pieces: the king on d1 and the rook on c1 trade places.
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 ThroneGuard family; read right to left it becomes position 599.
The engine's main line opens with g4.
Every sentence here is computed from the setup itself and can be checked on the board.
Balance
MBI 80 Morozov Balance Index: 80 of 100 — class A — most balanced.
- Engine evaluation of the starting position: +17 centipawns for White (depth 46, 400 000 000 nodes).
- Rank 198 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 → +25 → +27 → +9
Position facts
- Mirror twin: position #599
- The king starts on d, the rooks on c and h
- 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 f6 — Chess960 specifics · 780
- Attack on the uncastled king: bishop to e6 (d5) — Chess960 specifics · 780
- Attack on the uncastled king: pawn to d5 (c4·80) — Chess960 specifics · 780
- Winning blow: queen to d4 (h8) — Chess960 specifics · 970
- Attack on the uncastled king: bishop to c7 (e5·5) — Chess960 specifics · 1200
- Winning blow: rook to d8 (d1·21) — Chess960 specifics · 1280
- Winning blow: knight to c4 (e3·5) — Chess960 specifics · 1390
- Mate in 3: queen to a4 (h4) — Chess960 specifics · 1630
- Winning blow: queen to a3 (c1·3) — Chess960 specifics · 1870
- Chess960 tactic on d6 (b5) — Chess960 specifics · 2400
This position appears in course day 32
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Commentary
Long castling swaps the king on d1 with the rook on c1 — and in the engine's line it is Black who castles that way first. After g4 f6 b3 Black plays O-O-O, and the line ends f4 b6. A bishop is closed into the corner on a1 with a single diagonal to h8; the second is on f1. Among the pawns, a2 begins without a defender. The queen is on g1, the knights on b1 and e1.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.