The direction of play is a higher level concept in the opening, relating to the efficiency of stones played on the board. This involves the important trade-off between overconcentration (korigatachi) and vagueness - between playing a move that accomplishes too little and a move that tries to accomplish too much. Additionally, the stones already played are taken into consideration. The players aim not only at making efficient new moves, but also at playing moves that heighten the value of their previous moves, and at achieving maximum harmony in a global sense. One must strive to make each stone played important and valuable, that is, utilize its aji to the fullest extent possible. Thus, choosing the correct direction of play requires not only a deep understanding of the value of thickness, but also demands a good sense of positional judgment from the players.