Positions with an isolani in the center are very popular in today's game practice. World champion G. Kasparow and his challenger A. Karpow demonstrated a masterful handling of such positions in their duels. The individual pawn in the center can - depending on the circumstances in the game - prove to be a strength, but also a weakness. The centralized isolani problem is a key element of middlegame theory, and the argument about advantages and disadvantages runs through chess history. The two authors show the different procedures in positions with an Isolani and categorize them according to certain characteristics. Using numerous examples from recent tournament practice, particularly characteristic game moves are shown both for the organization of the attack and for the defense against the Isolani.