Starting position #706
Back-rank setup: BRKQNBNR
SP-706 · BastionGuard — Both knights begin inside the board while the king stands on c or f; a position and its mirror twin share this family.
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 h1, the queen on d1.
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, f2.
The setup belongs to the BastionGuard family; read right to left it becomes position 439.
The engine's main line opens with Ngf3, bringing the knight out to f3.
Every sentence here is computed from the setup itself and can be checked on the board.
Balance
MBI 59 Morozov Balance Index: 59 of 100 — class B — balanced.
- Engine evaluation of the starting position: +24 centipawns for White (depth 42, 400 000 000 nodes).
- Rank 392 of 960 by balance — 1 is the most balanced start.
- Balance band S — slight edge · dynamics along the play-out: equalizing
- Evaluation along the engine's main line (60 half-moves): +46 → +8 → -3 → 0
Position facts
- Mirror twin: position #439
- The king starts on c, the rooks on b 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
- Winning blow: knight to a3 (c2·2) — Chess960 specifics · 780
- Attack on the uncastled king: rook to e4 (b4) — Chess960 specifics · 780
- Winning blow: king to d1 (c1·3) — Chess960 specifics · 970
- Winning blow: king to d1 (c1·10) — Chess960 specifics · 970
- Attack on the uncastled king: bishop to g4 (e2·5) — Chess960 specifics · 1110
- Attack on the uncastled king: king to b2 (c1·16) — Chess960 specifics · 1280
- Mate in 2: knight to c6 (b4·2) — Chess960 specifics · 1320
- Castling-960 to the rescue on h1 (c1·3) — Castling-960 · 1340
- Mate in 3: rook to b5 (b2) — Chess960 specifics · 1760
- Winning blow: queen to c8 (c3·3) — Chess960 specifics · 2100
This position appears in course day 79
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Commentary
Both knights can reach f3 on move one, so the engine's first move needs a letter to say which: Ngf3, the one from g1. The king already stands on c1, so long castling moves the rook alone from b1. A bishop is shut into the corner on a1 with a single diagonal to h8; the second bishop is on f1. Two pawns begin with no defender at all: a2 and f2. The queen is on d1 beside her king, and the line runs Ngf3 e6 c4 c5 Nd3 Qc7.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.