Fujiko Fujio A (Motoo Abiko). It is an initial ninja manga that started in 1964. By the way, the name of Hattori is inspired by Hattori Hanzo.
A main character, Ken’ichi Mitsuba that is a primary school children is bad both exercise and study. Meanwhile, a little ninja named Hattori Kanzo befriends Ken’ichi. Hattori helps Ken’ichi with his problems as a good friend.
*List of Japanese subculture