As a family name, it seems to be:

後藤

where the first character means "behind" or "back" and the second character refers to wisteria vines.

(The first character is familiar to some of the martial arts practitioners, because it has an alternative pronunciation, "kō" instead of "go", which is used in the expression "kō-kutsu-shitsu", which is normally abbreviated to "kō-kutsu", and which means "with the back knee bent".)