Ude-Hishigi-Sankaku-Gatame(腕挫三角固?), also referred to as Ao muke gata ude hishigi(背中方腕挫?) in the Canon Of Judo, is one of the official 29 grappling techniques of Kodokan Judo. It is one of the nine joint techniques of the Kansetsu-waza list, one of the three grappling lists in Judo's Katame-waza, enumerating 29 grappling techniques, and is also demonstrated by Kyuzo Mifune in the video The Essence of Judo.
Sankaku is translated as "triangle," Ude-Hishigi as arm break, with gatame roughly translated as control. The triangle is formed by the legs of Tori that cross behind the head of Uke. The form created by the crossed legs resembles a triangle, hence the name. Sankaku-waza is a term that includes several control techniques (levers, chokes and fixed assets) that are characterized by this particular method of maintaining control with the legs.