These 9 schools of Bujinkan were first together in the lifetime of Toshitsugu Takamatsu, who then passed them on to Hatsumi Sensei.
These schools became available to westerners only in Hatsumi Sensei’s lifetime, and to Americans only as recently as the seventies. At that time there were very few students, all of whom traveled to Japan to receive teaching from Hatsumi Sensei. Today there are just over one thousand people worldwide who hold the rank of Shidoshi (5th dan and above), and are recognized instructors of the art.
The ninja history dates back for many centuries, as long as man operated in groups, there was a need for “behind the scene forces.” They would have developed a variety of arts using stones, sticks, vines and whatever nature provided. Legends say that the use of Shinobi (ninjas) was used as early as the 6th century.
The art of ninjutsu was also influenced by overseas. There are techniques, which were brought from China in the 7th century. Some of these we know today as Senban-nage (throwing of thin iron plates) and Hicho-jutsu (misunderstood to mean “leaping”, but actually meaning to neutralize an opponents technique). In addition, ninjutsu was influenced by spiritual practices such as different forms of meditation and also other philosophies such as Qimen Dunjia, divination related to Feng Shui. (Taken from “The Way of the Ninja”)