Etymology and distribution of 貞由.

Sadayoshi 【貞由】^{レベル1
Very rare}  The Japanese surnames etymology dictionary.

Yamagata-ken , Hokkaidou , Miyagi-ken . Thing . Heterogeneity of 白旗 . Yamagata-ken Tsuruoka-shi Baba-cho was a Shonai clan of the clan office, Miyagi-ken Sendai-shi Aoba-ku Kawauchi was in the Edo era in the Sendai Samurai of the Clan office. 源 Minamoto reference.

※ Miyagi-ken Shibata-gun Shibata-machi Tsukiba Hirata is a place name unknown in the record era. It is distributed in the same place.