Etymology and distribution of 久下井.

Kugei 【久下井】^{レベル1
Very rare}  The Japanese surnames etymology dictionary.

Nagano-ken , Gunma-ken , Toukyou-to . Summary . Synthesis of Konomi, Suda and Tada. Nagano-ken Minamisaku-gun Sakuho-machi Folklore in Okinawa. In the same place tells Mr. Tada called the first name last name in the Kamakura period. 小名 Ona reference. 須田 Suda reference. 多田 Tada reference. There is also a tale of Oda and Suda's synthesis separately here. 小田 Oda reference.