The Symmetrical Variation. Play varies greatly depending on how White chooses to develop. For instance, 2. Nf3 signals that White will try to achieve a favourable break with the d-pawn immediately and Black can then try to impede this break and achieve his own immediate d-pawn break. 2. Nc3 on the other hand makes it harder for Black to achieve that pawn break and signals White's intention to develop first and then break the symmetry. For instance, common moves for White in this variation include g3, Bg2, e4, Nge2, d3, and O-O (the arising white pawn structure is called the Botvinnik system) with the idea of a pawn break on f4, b4, or even d4. White may also play e3 instead of e4 and once the knight gets to e2 the pawn break on d4 becomes a very attractive possibility.

Wikipedia has related information at English Opening.

• Kasparov, Garry, & Keene, Raymond 1989 Batsford chess openings 2. ISBN 0-8050-3409-9.