Letters which were considered to be written by Keikichi TAUCHI (TAKECHI's real younger brother) and so on tell that since his house stood in Shichiken machi, Izo was also disdainfully referred to as '七以.'
以蔵はまた、家が七軒町にあったことから「七以」と軽蔑的に呼ばれていたことも、田内恵吉（武市の実弟）などの書簡として伝えられる。