Starting position #735
Back-rank setup: RKNQNRBB
SP-735 · RampartGuard — King pushed to the b- or g-file, knights off the edges — 144 positions here.
Move the pieces right on the board — full Chess960 rules, castle by dropping the king on the rook.
Position features
The king starts on b1, the rooks on a1 and f1, the queen on d1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
The pawn on b2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the RampartGuard family; read right to left it becomes position 416.
The engine's main line opens with a4.
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. f4 gxf4 3. a4 a5 4. Rxf4 Ned6 5. g4 h5 6. h3 Ra6 7. d3 f5 8. gxf5 e6 9. Qe2 exf5 10. e5 Re8
Evaluation after the line: +0.21 for White.
Best first moves for White (evaluation in pawns):
- e4 — +0.27
- a4 — +0.25
- g3 — +0.19
Balance
MBI 20 Morozov Balance Index: 20 of 100 — class D — largest edge.
- Engine evaluation of the starting position: +37 centipawns for White (depth 47, 400 000 000 nodes).
- Rank 765 of 960 by balance — 1 is the most balanced start.
- Balance band M — moderate edge · dynamics along the play-out: stable
- Evaluation along the engine's main line (60 half-moves): +32 → +11 → 0
Position facts
- Mirror twin: position #416
- The king starts on b, the rooks on a and f
- King and rook are neighbours — castling from adjacent squares feels unusual
- It becomes the daily position in 324 days
Puzzles from this position
- Attack on the uncastled king: queen to a5 — Chess960 specifics · 780
- Winning blow: rook to e6 (e5) — Chess960 specifics · 920
- Winning blow: knight to c1 (a2) — Chess960 specifics · 970
- Winning blow: pawn to b5 (a4·8) — Chess960 specifics · 1060
- Winning blow: pawn to b7 (c6·7) — Chess960 specifics · 1200
- Winning blow: bishop to d5 (h1·16) — Chess960 specifics · 1340
- Winning blow: queen to b5 (b4·3) — Chess960 specifics · 1430
- Mate in 2: knight to c5 (d7) — Chess960 specifics · 1670
- Mate in 3: rook to a8 (a1·3) — Chess960 specifics · 1980
- Mate in 3: bishop to d7 (b5) — Chess960 specifics · 2210
This position appears in course day 114
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Commentary
Short castling is two half-moves in one here: the rook already occupies f1, and the king still has five squares to travel to g1. A bishop holds the corner on h1 with one diagonal to a8; the second bishop is on g1. On the second rank, b2 leans on the king alone; no other second-rank pawn starts short of a defender. The queen is on d1, the knights on c1 and e1, the second rook in the corner on a1. White's edge here is a wide one, +37 centipawns: a4 a5 e4 g5 f4 gxf4.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.