Etymology and distribution of 瀬安.

Seyasu 【瀬安】^{レベル2
About 10}  The Japanese surnames etymology dictionary.

Kanagawa-ken Yokohama-shi Asahi ku. A variant of 葛貫 . 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. 葛貫 Kuzunuki reference.