Starting position #339
Back-rank setup: BNRKQRNB
SP-339 · ThroneGuard — Both knights start on inner files (b–g) while the king sits centrally on d or e — one of 204 positions filed 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 d1, the rooks on c1 and f1, the queen on e1.
Castling long simply swaps the two pieces: the king on d1 and the rook on c1 trade places.
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 ThroneGuard family; read right to left it becomes position 323.
The engine's main line opens with g4.
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. f4 f5 2. b3 b6 3. Nf3 Nf6 4. O-O-O e6 5. d3 O-O-O 6. g3 g6 7. Bb2 Qe7 8. e3 d6 9. e4 fxe4 10. Ng5 Bb7
Evaluation after the line: -0.04 for White.
Best first moves for White (evaluation in pawns):
- f4 — +0.35
- g4 — +0.34
- b3 — +0.30
Balance
MBI 89 Morozov Balance Index: 89 of 100 — class A — most balanced.
- Engine evaluation of the starting position: +14 centipawns for White (depth 48, 400 000 000 nodes).
- Rank 112 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 (70 half-moves): +27 → +9 → 0 → 0
- Deeper check (1 200 000 000 nodes, depth 50): +14 cp, 0 cp against the base run — verified
Position facts
- Mirror twin: position #323
- The king starts on d, the rooks on c and f
- King and rook are neighbours — castling from adjacent squares feels unusual
- It becomes the daily position in 439 days
Puzzles from this position
- Winning blow: pawn to e3 — Chess960 specifics · 780
- Attack on the uncastled king: bishop to h8 (a1·5) — Chess960 specifics · 780
- Winning blow: bishop to h8 (a1) — Chess960 specifics · 780
- Winning blow: pawn to e3 (d2·6) — Chess960 specifics · 920
- Winning blow: rook to b8 (b1·8) — Chess960 specifics · 1060
- Winning blow: king to a1 (b1·20) — Chess960 specifics · 1250
- Mate in 2: queen to c7 (a5·2) — Chess960 specifics · 1450
- Mate in 3: queen to a8 (d5) — Chess960 specifics · 1630
- Mate in 3: queen to a6 (a3·2) — Chess960 specifics · 1760
- Chess960 tactic on e7 (e3) — Chess960 specifics · 2250
This position appears in course day 49
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Commentary
Long castling swaps the king on d1 with the rook on c1; short castling moves the king alone, because the rook already stands on f1. Both corners hold a bishop, a1 towards h8 and h1 towards a8, each with a single diagonal. The queen begins on e1 beside her king, the knights on b1 and g1. The pawns on a2 and h2 both begin with no defender at all. The engine keeps the edge small, +14 centipawns, and pushes on the kingside: g4 g6 f4 f5 g5 d6.
Written from the measured facts above and checked against the board before publishing. All 960 positions have one.