Seidokaikan (正道会館) is a style of full contact karate, or Knockdown karate, founded by Kazuyoshi Ishii in 1980.
First formed in 1980 by Kazuyoshi Ishii, a former Kyokushin Karate practitioner who began his training under Hideyuki Ashihara in 1969. In 1980 Ishii left Kyokushin to join Ashihara's
new style and organization, but after only a few months he left to form his own style and the Seidokaikan organization. Seidokaikan arranged several successful challenge events
against other martial arts organizations, loosely based on the Kyokushin Knockdown karate rules as SeidoKaikan also allows grabbing.
In 1993 Mr. Ishii founded the K-1 organization as a kickboxing organization, with many students from Seidokaikan. Seidokaikan is world renowned and also has international dojos in many
countries including Australia.