Executed by moving down and forward and pressing any kick button while in midair, Yun and Yang perform a Dive Kick while falling at an angle determined by the kick button used. In Super Street Fighter IV: Arcade Edition, Yun and Yang will also angle their bodies based on the given angle.
The move is a solid tool for air-to-ground approaches and cross-ups, and can be used to bait (and possibly trade hits with) anti-airs from the opponent; the move must be used with precision, proper button choice, and good timing, or else the player risks giving the opponent an easy punish.
The Street Fighter IV series alters the hitboxes for each version of the move; it also has faster startup and a lower height restriction (moreso in Yun's case than Yang's), making the stronger versions much more favorable for long-range poking. Later editions of Super Street Fighter IV: Arcade Edition would increase the hurtboxes and height restrictions for the move for both twins.