Etymology and distribution of 新樂.

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

Saitama-ken Kounosu-shi . 細井 surname available.

※ Mie-ken Yokkaichi-shi There was a case in Saoi-machi where 729 (the first year of Tenpyo) gave Saoi surname. Later Changed to Sioi surname. 曽井 Soi reference.