Seigo Yamaguchi (山口 清吾 Yamaguchi Seigo?, 1924 - 1996) was a 9th dan aikido instructor and important teacher in the Aikikai. According to Mitsugi Saotome, before he was sent to Burma in 1958, he was the most prolific teacher at Aikikai Hombu Dojo.
Seigo Yamaguchi was born April 13, 1924 in Fukuoka, Japan. After his early education, he entered the navy where he was eventually to carry out a Kamikaze suicide mission, but was saved by the end of the World War II. He was introduced to Morihei Ueshiba in 1950, and entered the Aikikai in 1951. In 1958 he was sent to Burma to teach aikido to the army. Beginning in 1961 he again taught at the Aikikai Hombu Dojo; He also taught at his own dojo and at Meiji University.
- Nanaura, Fuyuo; Pranin, Stanley (1997), "Interview With Seiichi Sugano", Aikido Journal 112, retrieved April 12, 2012
- "Seigo Yamaguchi: In memoriam", Aikido Journal 108, 1996, retrieved April 15, 2012
- Pranin, Stanley (1991), "Interview with Mitsugi Saotome (1)", Aiki News 89, retrieved April 16, 2012
- Interview with Seishiro Endo
- Interview with Takeda Shihan
- Biography of Christian Tissier Shihan
- "Timeline". Yamaguchi Dojo.
- "Bio". Yamaguchi Dojo.
- The Encyclopedia of Aikido. Aikido Journal. Retrieved April 12, 2012.