Etymology and distribution of 定国.

Sadakuni 【定国】^{レベル3
About 300}  The Japanese surnames etymology dictionary.

Tochigi-ken .

① Tochigi-ken Nasukarasuyama-shi Hakuhisa, Nasu-gun Nakagawa Town originated in Hakuhisa. A place name with a record since the Edo period.

② One name in the Amami archipelago of Kagoshima-ken White and His exist. In Kagoshima-ken Amami-shi it's silk. 白 Haku reference. 久 Hisashi reference.