|Debut (Manga)||Chapter 92|
Shundō (瞬動術, Instant Movement) is a movement technique. By focusing ki or mana into the feet, the practitioner can cross a limited distance in a burst of extreme speed (enough to appear almost instantaneous). However, unlike true teleportation, the movement itself can be intercepted, and the exit point calculated; once began, the technique cannot be stopped. It must also be performed on some sort of foothold or surface.
However, the biggest weakness to Shundō is it's predictability, both the entry and the pull out, the essential components of Shundō can be calculated and "predicted" allowing them to counter your attack, because once in motion, you are unable to stop, you are powerless against interceptions.
Note that Shundō is just a generic term for the many variations of similar techniques in many different martial art styles.