The Koryuken is a special attack used by Dan. Like many of his moves, it is a parody of an existing "shoto-style" move (in this case, the Shoryuken). It is likely that this is a move created from Dan's limited understanding of the Shoryuken gained while briefly under Gouken's tutelage.
Input
+ 
Description
Executed the same as the Shoryuken, the Koryuken is also visually similar to the original move - a jumping uppercut with the fist half-extended, and the knee corresponding to the punching hand raised. The punch button used determines the damage, distance, and height; light punch has the least height, damage, and distance, while hard punch has the most, and medium is a balance of the two. In Street Fighter IV, the move gains an EX version that hits twice, but deals less damage than the heavy punch version.
In Street Fighter Alpha 3, Dan would randomly flash before executing the move. Should he flash, he gains invincibility during the attack. Due to its random nature, the flash has no value as far as tactics go. In Street Fighter IV, the invincibility of the move is instead determined by the button(s) used, with light giving none and the EX version giving the most of the other three.[1]
Sprite
Screenshots
