Kubota 【久保多】2 The Japanese surnames etymology dictionary.
① It tells from the place name of Kotomaru (Old: Karumaru) which was near Ibaraki-ken Mito-shi (formerly Yoshida village). Period, location unknown. 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.
② Ooita-ken Bungotakada-shi Originated from the waterside (old: Kuman). A place name with a record in the Warring States Period. It was the notation of "Hong Kong" in the same era during the Warring States Period. It is unknown whether it will exist.