October 10, 1859 – April 25, 1943
Takeda Sokaku was a renowned martial arts master of Daitō-ryū Aiki-jūjutsu (大東流合気柔術) and Ono-ha Itto-ryu swordsmanship. During his lifetime he is credited with teaching many famous martial artists among them the swordsman Shimoe Hidetaro, Aikido founder Ueshiba Morihei, as well as many politicians, military officers, judges, policemen, and other persons of high social standing from all over Japan. An astute if not paranoid businessman, Takeda, kept meticulous records of his student registrations and to those he awarded menjo including the terms under which he expected remuneration.
December 14, 1883 – April 26, 1969
Morihei Ueshiba, was a skilled exponent and teacher of Daitō-ryū Aiki-jūjutsu. He awarded certificates in Daitō-ryū to many of his recognised first generation (pre-war) students which later were equated to 8th Dan in Aikido. To separate himself from his teacher, Takeda Sokaku, he eventually changed the name of what he was teaching to Aiki-Budo and Aiki-jūjutsu which was later changed to Aikido. As Ueshiba grew older, less physically able and more spiritual in his outlook, his focus on teaching waned. It was during this time that his son, Kisshomaru Ueshiba, and other seniors made adjustments to the curriculum and teaching methods to what is now taught in mainstream Aikido schools. After his death, and another period of reorganisation, Kisshomaru took on the mantle of Doshu (hereditary head) and oversaw the formation of the Aikikai Honbu organization and the promotion of 'Aikikai' Aikido worldwide.
March 15, 1900 – December 25, 1979
Kenji Tomiki was the first student to be awarded an 8th Dan by the founder of Aikido, Morihei Ueshiba. A renowned and active teacher of both Judo and Aikido throughout his life, Tomiki shihan, referencing the methods of his Judo teacher, Jigaro Kano, formulated a method of teaching Aikido suitable for adoption by universities as well as introducing competitive Aikido (Aikido kyogi) into regular practice. A rift occurred with Kisshomaru Ueshiba and others in of the Aikikai in respect to this approach, leading to his eventual departure and resignation as a senior instructor in the Aikikai honbu. This led to Tomiki shihan forming the Japan Aikido Association (JAA) and establishing the Shodokan Dojo in Osaka, where he continued his research. Aikido taught using the teaching and practice methods of Kenji Tomiki is referred to as Shodokan Aikido (昭道館合気道), Tomiki Aikido (富木合気道) and/or Sport Aikido. Read more about Kenji Tomiki and Shodokan Aikido here