The Omi Alliance[note 1] (近江連合, Ōmi Rengō) is a yakuza group based in Osaka, of western Japan. It is the largest yakuza group in Japan, surpassing the eastern/Kanto-based Tojo Clan (which the Omi often clashes with) by several thousand members. At its height, the group boasted up to 35,000 members across 120 subsidiary families.
According to what Masaru Watase wrote in his letter to the Osaka Prefectural Police, the Omi Alliance is a little over 100 years old by that point; which would place its founding somewhere in the first two decades of the 20th century.
In December 1986, Omi Alliance is involved in the Empty Lot dispute, as well as being responsible for Goro Majima's capture after he was expelled from the Tojo Clan following the failed Ueno Seiwa hit three years prior.