Interruptibility
Interruptible as soon as frames, abbreviated "IASA frames," are the period of time at which an attack can be interrupted with another motion. They are usually found after hitboxes have disappeared. This period of time is often distinct from the amount of time it takes for the attack animation to finish. One attack that particularly exemplifies the concept is Marth's down tilt, which can be interrupted during the vast period of time Marth is retracting his blade, and Young Link's up smash. Perhaps the most notable example is Pichu's right facing taunt, which can be canceled after 60 frames, while the animation takes an entire 100 frames to complete. Peach can use IASA frames to perform the Vidjo-cancel and Vidjo-drop.
Brawl introduces the concept of "selective IASA", in which an action can only be interrupted by specific other actions, and the previous action may partially continue at the same time. This is used to prevent double jump cancelling, among other things.
