armbar
The armbar or the jūji-gatame (十字固, rendered as "Ude-Hishigi-Juji-Gatame") is an official Kodokan Judo technique.
The English word "bar" is used here to signify the opponent's extended arm, while the Japanese word "jūji" (十字) refers to the armbar's visual resemblance to the number 10 as written in kanji, 十. The word jūji is also found in "jūjika" (十字架), meaning a cross.
In general, the practitioner secures an arm at the wrist of the opponent, trapping it by squeezing the knees together. The attacker's legs end up across the opponent's chest, with the arm held between the thighs, with the elbow pointing against the thigh or hips. By holding the opponent's wrist to the attacker's chest with the pinky finger on the sternum and the thumb facing up (arm semi-supinated or semi-pronated), the practitioner can easily extend the opponent's arm and hyperextend the opponent's elbow. The attacker can further increase the pressure on the elbow joint by arching their hips against the elbow.