These need to be mastered in order to plan tactics etc in the middle game. Some fascinating examples recently on this site. (Dec 2006). Chess seems infinite, and is an example of a controlled chaos.
Outside passed pawn - struggle for 'the square' ... f4! ..f3! A Nimzowitsch vs Tarrasch, 1911 (C45) Scotch Game, 39 moves, 0-1
Kibitzing
