a4 because h4 weakens your kingside a little
what if your planning on castling queenside?
Do you mean 1.a4 or 1.h4 as an opening, or do you want to know which one is better to make first?
h4 because a4 weakens your queenside a little
1. a4 h5 2. a5 h4 3. a6 h3 the a pawn attack opening vs the h pawn counter-attack who will win?