Uraken Hizo Uchi is a technique in Kyokushin karate. It translates to 'Back Fist Kidney Strike.' This technique involves delivering a strike with the back of the fist to the opponent's kidney area. The term 'Uraken' refers to the back fist, 'Hizo' indicates the kidney, and 'Uchi' refers to the strike. It is commonly used to target the lower back or sides of the opponent's torso with precision and force.