About this opening
Catalan Opening: Open Defense, Classical Line is an opening in the Encyclopedia of Chess Openings,
classified under code E05. ECO group E (E00–E99)
covers Indian defences against 1.d4, covering the Nimzo-Indian, Queen's Indian, King's Indian and Catalan systems. This particular variation is reached
after 10 half-moves from the
starting position, with the move sequence 1. d4 Nf6 2. c4 e6 3. g3 d5 4. Bg2 dxc4 5. Nf3 Be7.
It belongs to the Catalan Opening family.
Within that family this is a level-2 branch (the Open Defense → Classical Line line). The immediate parent line is Catalan Opening: Open Defense, transitioned via 5…Be7.
The opening sequence in prose form: 1.d4 Nf6, 2.c4 e6, 3.g3 d5, 4.Bg2 dxc4, 5.Nf3 Be7. From this position the encyclopaedia records no further canonical continuations — practical play branches into unnamed transpositions or returns to the parent line for alternative ideas.