What is the best opening if your opponents starts with d4 and does not play queens gambit
easy question to answer
except for one thing
1.d4 c5 destroys Queen's gambit.
1.d4 Nf6 2.Bf4 c5 destroys London system.
The problem of 1.d4 Nf6 2.Bf4 c5 is that you have to deal with 1.d4 Nf6 2.Bg5, so I think 1...c5 is better.
