The Japanese surnames etymology dictionary.
① I have two 二瓶 last name. Fukushima-ken Motomiya-shi Records recorded in Shiraiwa in 1570 (Yongkang 3 years). Fukushima-ken Nishishirakawa-gun Yabuki-machi Tell that it is a pioneer in Kakeoka. Tochigi-ken Utsunomiya-shi In Tsuruta-machi Kyouto-fu Kyouto-shi is located next to the Imperial Palace and is called "Imperial side" and tells Niigata-ken Shibata-shi that he called the Sanbi surname. Last name is also written as "Sampei". 二瓶 reference. 三平 reference.