Aikikai, Martial arts organization in Tokyo, Japan

Aikikai is an aikido organization in Tokyo that operates from the Hombu Dojo and coordinates certified instructors worldwide in this Japanese martial art. Training covers defensive techniques including throws and joint locks taught through a structured curriculum.

Morihei Ueshiba opened the Kobukan Dojo in Wakamatsu-cho, Shinjuku, in April 1931. In 1940 the organisation was incorporated as the Kobukai Foundation, with Takeshita Isamu as its first chairman. After the postwar ban on aikido was lifted, it was re-registered in 1948 as the Aikikai, and in 2012 it became a Public Interest Incorporated Foundation.

The head of the Aikikai bears the title Dōshu, literally "Master of the Way", held by Morihei Ueshiba's descendants: Kisshomaru from 1969 and Moriteru since 1999. Because the Dōshu inherits the line and confers ranks rather than receiving them, he wears a white belt, not the black belt of ranked practitioners.

The Hombu Dojo stands in Wakamatsu-cho, Shinjuku, a short walk from the stations of the area. Training is held seven days a week in three rooms totalling about 250 tatami, the main one with 105 mats. Beginners' and regular classes are open to all practitioners who are or become Aikikai members, so arrange membership before travelling.

The organization maintains direct lineage to founder Morihei Ueshiba, with successive generations of his family continuing to lead it. This continuity in leadership is uncommon and gives the teaching methods special authenticity.