Aikido (合気道, Aikidō^?) is a Japanese martial art developed by Morihei Ueshiba as a synthesis of his martial studies, philosophy, and religious beliefs. Aikido is often translated as "the Way of unifying (with) life energy" or as "the Way of harmonious spirit." Ueshiba's goal was to create an art that practitioners could use to defend themselves while also protecting their attacker from injury.

Aikido is performed by blending with the motion of the attacker and redirecting the force of the attack rather than opposing it head-on. This requires very little physical strength, as the aikidōka (aikido practitioner) "leads" the attacker's momentum using entering and turning movements. The techniques are completed with various throws or joint locks.

Aikido derives mainly from the martial art of Daitō-ryū Aiki-jūjutsu, but began to diverge from it in the late 1920s, partly due to Ueshiba's involvement with the Ōmoto-kyō religion. Ueshiba's early students' documents bear the term aiki-jūjutsu.

Ueshiba's senior students have different approaches to aikido, depending partly on when they studied with him. Today aikido is found all over the world in a number of styles, with broad ranges of interpretation and emphasis. However, they all share techniques learned from Ueshiba and most have concern for the well-being of the attacker.

Moriteru Ueshiba (植芝 守央, Ueshiba Moriteru^?, born April 2, 1951) is a Japanese master of aikido. He is a grandson of Morihei Ueshiba, founder of aikido, and son of Kisshomaru Ueshiba. Ueshiba is the third and current Doshu (hereditary head) of the Aikikai.

Ueshiba was born on April 2, 1951, in Tokyo, Japan. Recalling his childhood during a 2004 interview, he said, "The first time I wore an Aikido uniform I was in the first grade of elementary school. But my family didn’t force me to do keiko (training) then, I just did it when I felt like it. I started training seriously in my high school years. My intention then was to become a successor to my father, and to preserve Kaiso’s [Morihei Ueshiba's] legacy for the future."

In 1976, Ueshiba graduated from Meiji Gakuin University with a degree in economics. In 1996, he assumed the position of Dojocho (director/owner) of Aikikai Hombu Dojo. In 1997, he visited Ireland. He assumed the title of Doshu on January 4, 1999, following the death of his father, Kisshomaru Ueshiba. In January 2006, as part of Aiki-Kai Australia's 40th anniversary, Ueshiba visited and taught in Australia.

Morihei Ueshiba (植芝 盛平, Ueshiba Morihei^?, December 14, 1883 – April 26, 1969) was a famous martial artist and founder of the Japanese martial art of aikido. He is often referred to as "the founder" Kaiso (開祖^?) or Ōsensei (大先生/翁先生^?), "Great Teacher".

Morihei Ueshiba was born in Tanabe, Wakayama Prefecture, Japan on December 14, 1883.

The only son of Yoroku and Yuki Ueshiba's five children, Morihei was raised in a somewhat privileged setting. His father was a rich landowner who also traded in lumber and fishing and was politically active. Ueshiba was a rather weak, sickly child and bookish in his inclinations. At a young age his father encouraged him to take up sumo wrestling and swimming and entertained him with stories of his great-grandfather Kichiemon who was considered a very strong samurai in his era. The need for such strength was further emphasized when the young Ueshiba witnessed his father being attacked by followers of a competing politician.

Ueshiba is known to have studied several martial arts in his life but he did not train extensively in most and even his training in Yagyū Shingan-ryū was sporadic due to his military service in those years. Records show that he trained in Tenjin Shin'yō-ryū jujutsu under Tozawa Tokusaburō for a short period in 1901 in Tokyo; Gotō-ha Yagyū Shingan-ryū under Nakai Masakatsu from 1903 to 1908 in Sakai, and judo under Kiyoichi Takagi 1911 in Tanabe. However, it was only after moving to the northern island of Hokkaidō in 1912 with his wife, as part of a settlement effort, that his martial art training took on real depth. For it was here that he began his study of Daitō-ryū aiki-jūjutsu under its reviver Takeda Sokaku. He characterized his early training thus:

Christian Tissier (born 1951 in Paris, France) is one of the best known European Aikido teachers, who pioneered the art in France. He started training in Aikido as a child in 1962, and trained under Mutsuro Nakazono in Paris until he left for Tokyo in 1969. He came to Aikikai Hombu Dojo as an 18 year old, and trained there for seven years. Among the teachers that have inspired him are Seigo Yamaguchi, Kisaburo Osawa and the second doshu Kisshomaru Ueshiba. While training at hombu dojo, he taught French language at a school and Institut franco-japonais de Tokyo.

He received 7th dan in 1998, and is among the handful of westerners who have been given the title Shihan by the Aikikai.

He is a founding member of the Fédération Française d'Aïkido Aïkibudo et Affinitaires (FFAAA or 2F3A) which was created in 1983. He is also a member of the technical college (Collège Technique) in charge of the Dan grades examination and of the awarding of teaching certifications: Brevet d'Etat and Brevet Fédéral. These examinatons take place jointly with members of the other federation, the Fédération Française d'Aïkido et de Budo (FFAB), within the Union des Fédérations d'Aïkido (UFA).

Steven Frederic Seagal (born April 10, 1952) is an American action film star, producer, writer, martial artist, guitarist and reserve deputy sheriff. A 7th-dan black belt in Aikido, Seagal began his adult life as an Aikido instructor in Japan. He became the first foreigner to operate an Aikido dojo in Japan.

He later moved to the Los Angeles, California, area where he made his film debut in 1988 in Above the Law. By 1991, he had starred in three successful films, and would go on to achieve greater fame in Under Siege (1992), where he played Navy SEALs counter-terrorist expert Casey Ryback. However both On Deadly Ground (1994, which he directed) and Under Siege 2: Dark Territory (1995) did poorly in theaters. During the later half of the 90s, he starred in three more theatrical films and a direct-to-video The Patriot. Aside from Exit Wounds (2001) and Half Past Dead (2002), his career shifted almost entirely to direct-to-video films (often low budget productions and shot in Europe or Asia). Between 1998 to 2009, he appeared in a total of 22 of these. At the age of 59, he returned to the big screen as Torrez in the 2010 film Machete. As of 2011, he's currently busy with the third season of his reality show Steven Seagal: Lawman.