Shokei (Akiyoshi) Matsui started Kyokushin Karate at the age of 13. In 1976, he joined the Kita Nagare-Yama Dojo in the Chiba prefecture of Japan, managing to achieve Shodan (first degree) Black Belt in a little over a year. In 1980, Matsui placed fourth in the 12th All Japan Open Karate Championships when he was just 17. Soon after, he became Chief Instructor of the International Kyokushin Headquarters School, "Honbu" Dojo in Tokyo, Japan.

Both in 1981 and 1982, Matsui took 3rd Place in the All Japan Open Karate Championships and then 8th place at the same event in 1983. He earned worldwide recognition and admiration for his amazing spirit, strength, and determination when he took a remarkable Third place finish at the 3rd World Open Karate Tournament in 1984. He succeeded in winning the All Japan Championships in each of 1985 and 1986, and then successfully completed the ultimate Kyokushin challenge, the "100 Man Kumite" in record time. In Japan, he became known as the man of "unparalleled genius", one who comes along but once in an eon, and then in 1987 became the youngest ever Champion of the World.

In May of 1992, Matsui opened his own school in Asakusa, Tokyo and was later appointed Branch Chief by Sosai Mas Oyama. On April 26, 1994, founder Sosai Mas Oyama regrettably passed away, leaving the Directorship of the worldwide organization to Matsui, who became "Kancho" (Director). In the wake of the Sosai's untimely death, and despite the well-documented backlash concerning his appointment, Kancho Matsui forged ahead that year staging the 11th All Japan Weight Tournament and the 27th All Japan Championships, the latter with a record 16,000 spectators in attendance. The following year, he produced the hugely successful, 6th World Open Karate Tournament, to which 168 fighters from all over the world competed and more than 25,000 spectators witnessed.

Kancho Shokei Matsui has planned, produced and presented numerous groundbreaking martial arts events to the world, including inaugurating the "World Cup"-Team Karate Championships, the "Women's World Karate Championships", the "World Weight Category Karate Championships", the "International Senior Karate Championships", the "International Kata Championships" and the "International Youth Karate Championships", to which nearly 2000 competitors aged 4-17 from around the world participated. These events are in addition to continuing the grand legacy Mas Oyama began by presenting the once-every-four-year, World Open Karate Tournament, and event that has grown to become the largest, most revered and renowned martial arts competition the world has ever seen. Currently, the International Karate Organization has over 12 million members in 125 countries. While simultaneously managing the organization from its headquarters in Japan, Kancho Matsui travels to Branches around the globe to teach and spread the spirit of the Kyokushin Way to countries and cultures everywhere. International Karate Organization Kyokushinkaikan Kancho　Shokei Matsui.