Masaaki Hatsumi (初見良昭 Hatsumi Masaaki, born 2 December 1931) is the founder and current Soke, or Grandmaster, of the Bujinkan Organization, currently residing and teaching in the city of Noda, Chiba, Japan.

He is also a doctor of orthopedics, specializing in the mending of bones.

Beginning in childhood, Masaaki Hatsumi studied several popular martial arts. After teaching martial arts to the U.S. soldiers stationed in Japan he noticed that the larger and stronger Americans had an advantage in battles when using the same techniques.

He began to question the legitimacy of modern martial arts training and started to search for one where persons of equal skill truly were equals, even if the other one was more muscular. It was after this time, while studying ancient Japanese weaponry, that he learned of ninjutsu and a martial artist named Toshitsugu Takamatsu who still knew it.

In 1957 he and Fukumoto Yoshio began making regular trips to train with his new teacher (who resided at the time in Kashiwabara, in Nara), taking a 15-hour train ride from his hometown of Noda in Chiba. This training continued for 15 years until the passing of Toshitsugu Takamatsu in 1972.
_{(quoted from Wikipedia)}