ECO A55: Old Indian Defense

ECO A55 is part of volume A — Flank Openings. The Lichess chess-openings dataset files one named line under it. It is Old Indian Defense: Normal Variation: 1. d4 Nf6 2. c4 d6 3. Nc3 Nbd7 4. e4 e5 5. Nf3.

That position has come up in 270,475 Lichess games between players rated 1600 to 2500: White won 48.9%, 6.0% were drawn and Black won 45.1%.