The back circular foot technique is basically a mawashi geri, which follows the opposite circular motion.

The targets of the ura mawashi geri are on the Chūdan and Jōdan levels. This challenging foot technique can hit targets at both the short and long distances. In the first option, the leg is strongly angled when snapping. The foot circles the target and then hits it from back to front. In the long distance, the target is hit with the leg almost extended. In both cases, the snap should be spot on at the time of the hit to create a whip effect.

Here you will find all information about the techniques in the video