While it is a truly wonderful technique, the weakness of the Hien is the strain it puts on the user’s wrist. But at this stage the user has become so accustomed to it that he can actually put together a series of them. Chimamire Tsubame Gaeshi is in essence a simple technique.
To actually invite for an attack to come, then while it has just been initiated, knock it off its course. Yet together with the mastery of the Hien, you keep the momentum by merely changing the direction after knocking the attack away and strike the opponent while he is caught off balance.