Two moves or one?

Sometime the question whether to make two moves with an initial pawn move or one can be vexing. Even first moves of the game, usually Black, can decide to play a pawn only one square ahead. 1. ..c6 the Caro Kann is a reputedly very strong defensive option, as is the Slav and Semi-Slav. Most often a pawn is only moved one square in order to support a pawn that has already moved two squares and help protect the space it occupies.