Daito-ryu Aiki Jujutsu is a traditional Japanese martial art which is said to be about one thousand years old. However, it was only opened to the public for the first time by Takeda Sokaku (1860-1943) one hundred years ago. All the people who had the opportunity to witness Sokaku Sensei's techniques were struck with wonder at his high level of skill. All types of jujutsu martial arts utilise the opponent's power. Sokaku Sensei's art was the same in this respect, except that in addition to ju, Sokaku Sensei utilised an additional power. He called it Aiki.