What if only the player who passed is allowed, at his next turn, to recreate a former position? Suppose White takes the ko in Dia. 3-5-1 and Black passes. If White takes the ko at 3, since Black is allowed at this turn to recreate a former position he can immediately retake the ko at 4. To let a player recapture a ko immediately seems strange, but it becomes possible if you rule that a player can recreate a former position on his next turn after passing. Now suppose White passes. Black takes the ko with 6 in Dia. 3-5-3, but since White has just passed with 5, next he can recreate a former position with 7. White 7 immediately recaptures Black 6, repeating the position after Dia. 3-5-1. Again we are caught in an endless cycle. If a player who passes is allowed to recreate a former position on his next turn, the whole purpose of prohibiting endless cycles is lost.