ECO A04

Colle System: Rhamphorhynchus Variation

Colle System: Rhamphorhynchus Variation is a chess opening classified under ECO A04. Its defining line here is 1. Nf3 c5 2. e3 g6 3. d4 Bg7 4. dxc5 Qa5+.

1. Nf3 c5 2. e3 g6 3. d4 Bg7 4. dxc5 Qa5+

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The diagram shows the position after 1. Nf3 c5 2. e3 g6 3. d4 Bg7 4. dxc5 Qa5+. Play through it move by move in the interactive explorer.

Opening name, ECO code, and main line come from the Lichess open chess openings dataset.