Starting position #641
Back-rank setup: BRNBKRQN
SP-641 · ThroneScout — King in the middle of the rank, with a knight already committed to the 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 e1, the rooks on b1 and f1, the queen on g1.
The kingside rook already stands on f1, so castling short moves only the king, from e1 to g1.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
The pawn on d2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the ThroneScout family; read right to left it becomes position 219.
The engine's main line opens with b3.
Every sentence here is computed from the setup itself and can be checked on the board.
Balance
MBI 83 Morozov Balance Index: 83 of 100 — class A — most balanced.
- Engine evaluation of the starting position: +16 centipawns for White (depth 48, 400 000 000 nodes).
- Rank 155 of 960 by balance — 1 is the most balanced start.
- Balance band S — slight edge · dynamics along the play-out: volatile
- Evaluation along the engine's main line (60 half-moves): +23 → +7 → 0
Position facts
- Mirror twin: position #219
- The king starts on e, the rooks on b and f
- King and rook are neighbours — castling from adjacent squares feels unusual
- It becomes the daily position in 299 days
Puzzles from this position
- Attack on the uncastled king: queen to g2 (g1·2) — Chess960 specifics · 780
- Attack on the uncastled king: pawn to c4 (b3·31) — Chess960 specifics · 780
- Winning blow: knight to c5 (d3·3) — Chess960 specifics · 920
- Winning blow: queen to g6 (f6·2) — Chess960 specifics · 1060
- Mate in 2: queen to e5 (g3) — Chess960 specifics · 1320
- Winning blow: bishop to f6 (a1·13) — Chess960 specifics · 1560
- Mate in 3: rook to f6 — Chess960 specifics · 1630
- Mate in 3: queen to c7 (b7) — Chess960 specifics · 1630
- Attack on the uncastled king: rook to b8 (b3·5) — Chess960 specifics · 1760
- Winning blow: queen to a7 (e3·4) — Chess960 specifics · 1890
This position appears in course day 74
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Commentary
The rook already occupies f1, so short castling moves the king alone from e1. A bishop is closed into the corner on a1 with a single diagonal to h8; the second bishop is on d1. Among the pawns, d2 leans on the king alone; no other second-rank pawn starts short of a defender. The queen is on g1, the knights on c1 and h1 — the cornered one has g3 as its only move. The search ran to depth 48 and calls it +16 centipawns: b3 e6 e3 Nd6 g4 b6.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.