Starting position #835
Back-rank setup: BRKNRQNB
SP-835 · BastionGuard — The king starts one file off-centre, on c or f, with neither knight 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 e1, the queen on f1.
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 BastionGuard family; read right to left it becomes position 115.
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.
Opening: main line
Stockfish's main line from the start of this setup, 15 moves deep (100 million nodes per move):
1. e4 g5 2. g3 b6 3. Nh3 Qh6 4. Ne3 e6 5. Bg2 f5 6. exf5 Bxg2 7. Qxg2 exf5 8. f4 g4 9. Nf2 Nc6 10. O-O-O Qg6
Evaluation after the line: +0.17 for White.
Best first moves for White (evaluation in pawns):
- e4 — +0.34
- g3 — +0.27
- b4 — +0.26
Balance
MBI 55 Morozov Balance Index: 55 of 100 — class B — balanced.
- Engine evaluation of the starting position: +25 centipawns for White (depth 43, 400 000 000 nodes).
- Rank 416 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 (56 half-moves): +24 → +10 → 0
Position facts
- Mirror twin: position #115
- The king starts on c, the rooks on b and e
- King and rook are neighbours — castling from adjacent squares feels unusual
- It becomes the daily position in 88 days
Puzzles from this position
- Attack on the uncastled king: pawn to e5 (f4·17) — Chess960 specifics · 780
- Attack on the uncastled king: pawn to a5 (b4·8) — Chess960 specifics · 780
- Attack on the uncastled king: knight to d6 (b5·9) — Chess960 specifics · 920
- Winning blow: king to b2 (c1·14) — Chess960 specifics · 970
- Attack on the uncastled king: knight to d6 (b5·11) — Chess960 specifics · 1060
- Winning blow: bishop to d5 (h1·12) — Chess960 specifics · 1200
- Winning blow: king to b1 (c1·31) — Chess960 specifics · 1250
- Winning blow: king to c1 (b1·21) — Chess960 specifics · 1390
- Attack on the uncastled king: queen to b8 (b5·3) — Chess960 specifics · 1650
- Winning blow: knight to d3 (f4) — Chess960 specifics · 2060
This position appears in course day 54
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Commentary
Both bishops start in the corners, on a1 and h1, each with a single long diagonal — one to h8, the other to a8. The king already stands on c1, so long castling moves the rook alone; the rooks are on b1 and e1. Two pawns begin without a defender, a2 and h2, and the pawns on c2 and d2 lean on the king alone — four of the eight open without a piece behind them. The queen is on f1, the knights on d1 and g1. The engine takes the centre with e4, and White's edge is +25 centipawns: e4 e5 g3 b5 a4 bxa4.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.