When people ask me what martial art I study I will often just say "Jujutsu" or "Old Japanese martial arts" because I know that if I say "Ninjutsu" they will often raise and eyebrow and not take me seriously, but in truth Ninjutsu actually existed and is still passed down to today, and i have spend almost all my adult life studying it. Ninjutsu can be traced back almost a thousand years to the 11th century, and some scholars say even before that.
Ninjutsu today was passed down through Toshitsugu Takamatsu who was born in 1889. He received Sokeship (Grandmastership) of nine seperate martial arts traditions passed down by his teachers such as Shinryuken Masamitsu Toda and Ishitani Matsutaro and Mizuta Yoshitaro Tadafusa who themselves were grandmasters of Ninja and Samurai lineages. Takamatsu was the last real Ninja being employed on missions in Manchuria, Mongolia, and China in the 1920s. He took part in many real fights and killed many men in life and death struggles.
In the 1960s up until 1972 Takamatsu taught Dr Masaaki Hatsumi the arts of the Ninja and Samurai Traditions. Takamatsu made him Grandmaster of 9 seperate martial arts traditions. Today Dr Hatsumi has thousands of students throughout the world under the title of the Bujinkan although he has now officially retired from teaching.