October 10, 1859 – April 25, 1943
Takeda Sokaku was a reknowned 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 business man, 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 (O-Sensei), was a skilled exponent and teacher of Daitō-ryū Aiki-jūjutsu. He awarded menjo (certificates) in Daitō-ryū to many of his recognised first generation (pre-war) students which later were equated to 8th Dan in Aikido. To seperate himself from his teacher, Takeda Sokaku (and I assume associated financial commitments), he eventually changed the name of what he was teaching to Aiki-Budo and laterly Aikido. As Ueshiba grew older, less physically able and more spiritual in his outlook, his focus on teaching changed. It was during this time that many of his senior students made adjustments to the cirruculum and teaching methods to what is now taught in mainstream Aikido schools. After his death, and another period of reorganisation, his son Kisshomaru Ueshiba took on the mantle of Doshu (hereditary head) and oversaw the formation of the Aikikai Honbu organisation and the promotion of Aikdio worldwide.
March 15, 1900 – December 25, 1979
Kenji Tomiki was the first student to be awarded a teaching menjo (Menkyo Kaiden or license of transmission, equated later to an 8th Dan) by the founder of Aikido, Morihei Ueshiba. A renkowned and active teacher of both Judo and Aikido throughout his life, Tomiki, referencing the methods of his beloved Judo teacher, Jigaro Kano, formulated a new 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 other seniors in respect to this approach, leading to his eventual resignation as technical director of the Aikikai. This led to his formation of the Japan Aikido Association and the founding of the Shodokan Dojo in Osaka, where he continued his research and focus on promoting Aikido using these methods. Aikido taught using the teaching and practice methods of Kenji Tomiki is often 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