Starting position #818
Back-rank setup: BRKNQBRN
SP-818 · BastionScout — The king starts one file off-centre, on c or f, and a knight begins 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 b1 and g1, the queen on e1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
The second rank carries 2 pawns with no defender at all: a2, h2.
The setup belongs to the BastionScout family; read right to left it becomes position 135.
The engine's main line opens with d4, 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 86 Morozov Balance Index: 86 of 100 — class A — most balanced.
- Engine evaluation of the starting position: +15 centipawns for White (depth 45, 400 000 000 nodes).
- Rank 122 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 (70 half-moves): +20 → +75 → +20 → 0
- Deeper check (1 200 000 000 nodes, depth 50): +26 cp, +11 cp against the base run — not confirmed at depth · M — moderate edge
Position facts
- Mirror twin: position #135
- The king starts on c, the rooks on b and g
- 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 d5 (e4) — Chess960 specifics · 780
- Winning blow: king to b2 (c1) — Chess960 specifics · 780
- Attack on the uncastled king: king to d2 (c1·6) — Chess960 specifics · 920
- Winning blow: queen to f4 (e3·2) — Chess960 specifics · 1060
- Winning blow: queen to c8 (a6) — Chess960 specifics · 1290
- Winning blow: rook to g2 (g1·12) — Chess960 specifics · 1430
- Mate in 2: queen to c4 (e6) — Chess960 specifics · 1450
- Mate in 3: queen to a5 (d2·2) — Chess960 specifics · 1630
- Winning blow: queen to a8 (a3·6) — Chess960 specifics · 1870
- Chess960 tactic on b6 (f6) — Chess960 specifics · 2400
This position appears in course day 43
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Commentary
The king already stands on c1, so long castling moves the rook alone — and the engine does exactly that on its third move. A bishop holds the corner on a1 with one diagonal to h8; the second bishop is on f1. Two pawns begin without a defender, a2 and h2, and the pawn on c2 leans on the king alone. The queen is on e1, the knights on d1 and h1 — the cornered one has g3 as its only move, and the rooks are on b1 and g1. White's edge is a narrow +15 centipawns: d4 d5 Nc3 e6 O-O-O Nc6.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.