"Ugajin" is a folk religion god (Shinto) worshipped since the medieval period in Japan.
The shinmei (name of god) is believed to have derived from Ukano-mitama appearing in Japanese Mythology (some say it derived from 'Ugaya,' which is a Buddhist word meaning 'zaise' (the giving of wealth), but they are a minority), and it was originally a god worshipped among the people as god of spirit of grains and god of good fortune, similar to Ukanomitama-no-kami.
This was adopted in the education and learning of Enryaku-ji Temple on Mt. Hiei (Tendai sect), and syncretized with Benzaiten (Sarasvati, Buddhist goddess of music, learning, eloquence, wealth, longevity, and protection from natural disasters), a god of Buddhism. Thus, it is also referred to as Uga-benzaiten.
Worshipping of Uga-benzaiten spread nationwide centered around Chikubushima Island, Omi Province (Hogon-ji Temple), close to Enryaku-ji Temple, and Itsukushima-jinja Shrine in Aki Province, Enoshima-jinja Shrine in Sagami Province, etc. These became shrines enshrining Ichikishima-hime and other gods during the separation of Buddhism and Shintoism in the Meiji period. At Ugafuku-jinja Shrine in Kamakura City, Ugajin remains enshrined as a Shinto god.
Many people in the Tochigi region today live with under the Ugajin family name.