Rule 7.5 (3) states that when naval units move to an OZ where there are enemy units "The player who is executing a Strategy now has his Strategy Phase end." The Strategy Phase consists of a series of Initiative tests followed by Strategy ROUNDS. Each player doesn't have a Strategy Phase. It seems that moving into an enemy OZ should not end the entire PHASE. If that is the case, then in a Turn 5 where the Allies have just gained 10 RCs and have big offensive plans, the Japanese should try to get the initiative, run a CA into an enemy OZ, and end the entire Strategy Phase.