Yakuza call themselves ninkyō dantai (chivalrous organizations) which the Japanese media and police call them bōryokudan (violence group). They are the world's largest criminal organization and have about 103,000 members. The three biggest Yakuza families are Yamaguchi-gumi, Sumiyoshi-kai, and Inagawa-kai. During the 2011 Tōhoku earthquake and tsunami, they opened their offices to help refugees and sent dozens of trucks with supplies to affected areas.