The bujinkan dojo is a very old japanese line of schools , dating back to the 12th century . It is taught in japan by the world renowned martial artist Masaaki Hatsumi and is now in most countries of the world , being taught to over 2 million students . This art is for adults only ( 18 yrs and above ) as it is a battlefield martial art , but is not restricted to the fit and healthy , as true martial arts do not require speed and strength , but timing , distance and balance . Although most people know this art as Ninjutsu , it is properly called Budo Taijutsu . If you cannot do a martial art because of strength , or age , or body size ( women ) , then it will be no good when you become weaker , or older , or are defending against a much larger assailant . True martial arts are something you can practice well into old age and this practice has the benefits of slowing down that aging process . All classes are done in a relaxed and informal manner and are based on teaching self defence .