ECO family guide

Rat Defense — all variations and ECO codes

11 named lines across 5 ECO codes (A41–C00), spanning ECO volumes A, B, C. Source: the CC0-licensed lichess.org opening database.

The main line

Position after 1.e4 d6 2.f4 (B00). Open this line on Lichess → · Rat Defense: Harmonist on Lichess

How the main line scores at your rating

Real Lichess win rates for 1.e4 d6 2.f4, playing as white — the family's other variations are not separately tracked for win rate yet, main line only.

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Win/draw/loss rate by rating band
Rating band	Games	White / draw / Black	Score for white
1400-1600	737,592	52.6% / 3.1% / 44.4%	54.1%
1600-1800	1,291,742	51.8% / 3.4% / 44.9%	53.4%
1800-2000	1,358,665	49.7% / 3.8% / 46.5%	51.6%
2000+	678,409	47.8% / 4.6% / 47.6%	50.1%

All 11 named variations

Every named line in the Rat Defense family, from the CC0-licensed ECO classification — not separately tracked for win rate, but every ECO code and move sequence is real, sourced data.

A41English Rat — 1.d4 d6 2.c4 e5
- A41Lisbon Gambit — 1.d4 d6 2.c4 e5 3.dxe5 Nc6
- A41Pounds Gambit — 1.d4 d6 2.c4 e5 3.dxe5 Be6
A82Balogh Defense — 1.e4 d6 2.d4 f5
B00Antal Defense — 1.e4 d6 2.d4 Nd7
B00Fuller Gambit — 1.e4 d6 2.f4 d5 3.exd5 Nf6
B00Harmonist — 1.e4 d6 2.f4
B00Petruccioli Attack — 1.e4 d6 2.h4
B00Spike Attack — 1.e4 d6 2.g4
B06Accelerated Gurgenidze — 1.e4 g6 2.d4 d6 3.Nc3 c6
C00Small Center Defense — 1.d4 e6 2.e4 d6