Ushiro Geri Jodan is a technique in Kyokushin karate. It translates to 'Rear Kick to the Head.' This technique involves executing a kick with the rear leg to target the opponent's head from behind. The term 'Ushiro' refers to the rear, 'Geri' indicates the kick, and 'Jodan' specifies the head level. It is commonly used as a powerful and unexpected attack to strike the opponent's head with significant force.