Tokunaga 【徳奈賀】2 The Japanese surnames etymology dictionary.
① Tochigi-ken Tochigi-shi Originated from the vicinity of Toga Fujioka Town (formerly Numajiri). A place name with a record since the Warring States Period. Ibaraki-ken Shimotsuma-shi It was in the Azuchi-Momoyama period as a vassal of Mr. Taga Tani who was the castle owner of Shimozuma Castle in Honjo-cho. Ibaraki-ken Tsuchiura-shi I met a doctor in the middle of the Edo period.