Starting position #879
Back-rank setup: QRKRNNBB
SP-879 · BastionGuard — King shifted to c or f, knights kept clear of the edges — 168 positions in all.
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 d1, the queen on a1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
One second-rank pawn starts with no defender at all: e2.
The setup belongs to the BastionGuard family; read right to left it becomes position 80.
The engine's main line opens with b4.
Every sentence here is computed from the setup itself and can be checked on the board.
Balance
MBI 1 Morozov Balance Index: 1 of 100 — class D — largest edge.
- Engine evaluation of the starting position: +66 centipawns for White (depth 43, 400 000 000 nodes).
- Rank 947 of 960 by balance — 1 is the most balanced start.
- In 50 self-play games White scored 60.0% (95% CI 46.2–72.4%).
- Balance band L — large edge · dynamics along the play-out: volatile
- Evaluation along the engine's main line (60 half-moves): +72 → +52 → +26 → +6
Position facts
- Mirror twin: position #80
- The king starts on c, the rooks on b and d
- King and rook are neighbours — castling from adjacent squares feels unusual
- It becomes the daily position in 1196 days
Puzzles from this position
- Attack on the uncastled king: knight to e7 — Chess960 specifics · 620
- Attack on the uncastled king: pawn to b5 (a4·21) — Chess960 specifics · 780
- Winning blow: queen to e7 (f8) — Chess960 specifics · 920
- Winning blow: bishop to d7 (e8) — Chess960 specifics · 1010
- Winning blow: knight to e5 (f3·10) — Chess960 specifics · 1150
- Winning blow: queen to c5 (e7·3) — Chess960 specifics · 1250
- Mate in 2: queen to b7 (b6·3) — Chess960 specifics · 1450
- Mate in 3: rook to g7 (g4) — Chess960 specifics · 1630
- Winning blow: queen to g8 (c4·3) — Chess960 specifics · 1870
- Chess960 tactic on c7 (c4) — Chess960 specifics · 2350
This position appears in course day 3
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Commentary
The king already stands on c1, so long castling moves the rook alone; the rooks are on b1 and d1. The bishops sit together at the edge, on g1 and h1, and the cornered one has a single diagonal to a8. On the second rank, e2 is the one that begins without a defender — a central pawn bare on move one. The queen begins in the far corner on a1, the knights on e1 and f1, standing shoulder to shoulder. White's edge here is a wide one, +66 centipawns: b4 a5 a4 f5 Nd3 e5.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.