Caissa Codex
A51

Indian Defense: Budapest Defense, Fajarowicz Defense, Bonsdorf Variation

Chess diagram: Indian Defense: Budapest Defense, Fajarowicz Defense, Bonsdorf Variation after 4…b6

Type a move and press Enter: e4, Nf3, O-O, or from and to squares like g1f3 (e7e8q to promote). The board is also played with the mouse.

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Statistics from Lichess

18,344 games: White 52.2% / Draw 4.8% / Black 43.0%

The moves played next. Pick one to see it on the board.
Next moveGamesWhite / Draw / BlackW / D / B
7,4057,405
2,9242,924
2,4882,488
2,2522,252
765765
578578
542542
480480

Rated Lichess games between players rated 1600 to 2500, from the Lichess opening explorer, updated Oct 23, 2026

Engine evaluation

+1.54 White is clearly better

Even so, Black scores 45.4% here in practice: wins plus half the draws in rated Lichess games between players rated 1600 to 2500.

Best play: 5. g3 Bb7 6. Nf3 Bc5 7. e3 Be7 8. Bg2 d6 9. O-O dxe5

Stockfish 19, depth 30, after the line's last move. Scores are in pawns, from White's side.

Overview

Indian Defense: Budapest Defense, Fajarowicz Defense, Bonsdorf Variation (ECO A51, Flank Openings) is a variation of the Indian Defense: Budapest Defense, Fajarowicz Variation, reached after 1. d4 Nf6 2. c4 e5 3. dxe5 Ne4 4. a3 b6 (4 moves).

In 18,344 rated Lichess games between players rated 1600 to 2500, White won 52.2%, Black 43.0% and 4.8% were drawn. White's most played move here is 5. Nf3, in 40% of those games.

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How to play against the Indian Defense: Budapest Defense, Fajarowicz Defense, Bonsdorf Variation

5. Nd2 scores best for White: 59.7%, with White winning 56.9% and Black 37.4% of 2,252 games. The most played, 5. Nf3, scores 59.7% in 7,405 games, and 5. Qd5 scores lowest: 34.8%. Stockfish's first choice is 5. g3.

Main answers: those played in at least 5% of these games. Score: White's wins plus half the draws, in rated Lichess games between players rated 1600 to 2500. How to play against other popular openings

Other lines from the same position

Instead of 4. a3 b6, the position after Indian Defense: Budapest Defense, Fajarowicz Variation also goes on to:

Cite this page

Caissa Codex. “Indian Defense: Budapest Defense, Fajarowicz Defense, Bonsdorf Variation (A51)”. Lichess data as of 23 Oct 2026. https://chesscodex.org/openings/indian-defense-budapest-defense-fajarowicz-defense-bonsdorf-variation

https://chesscodex.org/openings/indian-defense-budapest-defense-fajarowicz-defense-bonsdorf-variation