Tsubasa Okubo

Joined the Seishinkan Satozuka Branch in 1998 (Heisei 10). He later trained under Shihan Inoue at the Atsubetsu Branch.
In 2005 (Heisei 17), at a training camp, he earned his 1st dan by completing a continuous 10-opponent kumite in which every opponent held branch-chief or shihan rank — Shihan Sumiyoshi, Shihan Inoue, Shihan Aoki, Assistant Shihan Sueyoshi, Branch Chief Takahashi, Branch Chief Fujiwara, Branch Chief Mizushiri, Branch Chief Inomata, and the late Director Mimura among them. The tenth and final opponent was President Katsumi Okubo himself, marking the President's official last kumite match.

After graduating from Shiroishi High School, he went on to Hokkaido Information University and then its graduate school (master's program).
He was appointed branch chief at age 19, becoming the second-youngest branch chief in the organization's history, after Akira Murakami, 1st dan (then a student, now serving with the Hokkaido Prefectural Police).
He earned his 2nd dan in 2008 (Heisei 20) and his 3rd dan in 2010 (Heisei 22), and after graduation joined the staff of the NPO All Japan Seishinkai.
In 2013 (Heisei 25) he was promoted to Associate Shihan and led an instructional expedition to Sri Lanka the same year. He earned his 4th dan in 2015 (Heisei 27) and received his full Shihan qualification the following year.
In 2018 (Heisei 30) he was awarded 6th dan Renshi and traveled to each branch as Chief Shihan.

In the summer of 2020 (Reiwa 2), he became the 4th-generation Headquarters Director.
As the official successor to the current President and Soke, he succeeded as 2nd-generation Soke (Acting ISKF President).
In the summer of 2023 (Reiwa 5), he traveled to the Sweden Branch. At an international seminar in Stockholm, he was awarded 7th dan in Shito-ryu by the International Shito-ryu Sanshinkan, an organization active in Sweden.

Alongside his karate activities, he runs Fujido Sports, a business dealing in karate equipment, automotive supplies, and related goods.