Starting position #439
Back-rank setup: RNBNQKRB
SP-439 · 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 f1, the rooks on a1 and g1, the queen on e1.
Castling short simply swaps the two pieces: the king on f1 and the rook on g1 trade places.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
The second rank carries 2 pawns with no defender at all: c2, h2.
The setup belongs to the BastionGuard family; read right to left it becomes position 706.
The engine's main line opens with g4.
Every sentence here is computed from the setup itself and can be checked on the board.
Balance
MBI 47 Morozov Balance Index: 47 of 100 — class C — noticeable edge.
- Engine evaluation of the starting position: +27 centipawns for White (depth 42, 400 000 000 nodes).
- Rank 506 of 960 by balance — 1 is the most balanced start.
- Balance band M — moderate edge · dynamics along the play-out: volatile
- Evaluation along the engine's main line (60 half-moves): +34 → +58 → +56 → +41
Position facts
- Mirror twin: position #706
- The king starts on f, the rooks on a and g
- King and rook are neighbours — castling from adjacent squares feels unusual
- It becomes the daily position in 221 days
Puzzles from this position
- Attack on the uncastled king: pawn to d4 (c3·6) — Chess960 specifics · 780
- Attack on the uncastled king: bishop to b2 (c1·2) — Chess960 specifics · 780
- Attack on the uncastled king: pawn to d4 (e3·16) — Chess960 specifics · 780
- Attack on the uncastled king: knight to c7 (d5·21) — Chess960 specifics · 920
- Winning blow: king to f2 (f1·10) — Chess960 specifics · 970
- Winning blow: queen to g5 (g7) — Chess960 specifics · 1060
- Mate in 2: bishop to h5 — Chess960 specifics · 1090
- Winning blow: queen to c4 (b5) — Chess960 specifics · 1280
- Winning blow: queen to g5 (e7·3) — Chess960 specifics · 1430
- Attack on the uncastled king: queen to g8 (g3·6) — Chess960 specifics · 1990
This position appears in course day 12
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Commentary
Short castling swaps the king on f1 with the rook on g1. A bishop holds the corner on h1 with one diagonal to a8; the second bishop is on c1. Two pawns begin with no defender at all: c2 and h2. The queen is on e1 beside her king, the knights on b1 and d1, the second rook in the corner on a1. The published line opens g4 e5, then d3 Ne6 Nbc3 Nc6.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.