To promote peace globally, Koyamada serves roles as Board of Directors and Goodwill Ambassadors
in networks of large municipals and international organizations around the world.


Sister Cities International (USA)

In 2017, Koyamada became the first native-born Japanese to elected as Sister Cities International (SCI)’s Board of Directors. Founded by President Dwight D. Eisenhower in 1956, SCI is a nonpartisan 501(c)(3) nonprofit which serves as the national membership organization for individual sister cities, counties, and states across the United States. This network unites tens of thousands of citizen diplomats and volunteers with over 2,000 partnerships in 150 countries. It promotes peace through mutual respect, understanding and cooperation - one individual, one community at a time.

Japan Karate Federation (Japan)

In 2016, Koyamada was appointed as Karate Ambassador for 2020 Tokyo Summer Olympics by Japan Karate Federation (JKF), a national governing body of Karate in Japan and an international member of World Karate Federation with 191 country members and 100 million practitioners around the world. Founded in 1969, JKF is organized for the purpose of bringing unified order to Karate in Japan. Since then, JKF has established the status of Karate as a national sport. After his appointment, Karate was officially added as the additional Olympics Game for the first time in its history for the 2020 Tokyo Olympics.

City of Kyoto (Japan)

In 2014, Kyoto Mayor Daisaku Kadokawa appointed Koyamada as Kyoto Goodwill Ambassador. Kyoto is most well known in Japanese history for being the former Imperial capital of Japan for more than one thousand years. It is one of the most popular tourist destinations and one of the country's ten largest cities with a population of 1.5 million people and a modern face. Countless world heritage temples, shrines and other historically priceless structures survive in the city today. Peaceful spirit of ancient and abiding Kyoto is founded throughout the city.

Okayama Prefecture (Japan)

In 2010, The Governor of Okayama Prefecture appointed him as the International Goodwill Ambassador. Okayama Prefecture is Koyamada's hometown where he was born and grew up. Okayama Prefecture, also known as "The Land of Sunshine" is located in the heart of Western Japan, with its population of approx. 2 million people. Some of the well known touristic destinations include; "Okayama Castle", also known as Crow Castle; "Kōraku-en", one of the Three Great Gardens of Japan; "Bikan Historical Quarter", where buildings from the Edo and Meiji eras are still preserved in City of Kurashiki; and "The Old Shizutani School", in use from 1673 to 1964, was Japan’s first public school and the only school to be designated a National Treasure.

Japan America Society of Southern California (USA)

In December 2010, Koyamada was appointed as Special Ambassador by Japan America Society (JAS) of Southern California, founded on February 21, 1909 to build economic, cultural, governmental and personal relationships between the people of Japan and America. It is recognized as a U.S. 501(c)(3) non-profit, charitable and educational organization consisting of individuals and corporations with an interest in Japan and in United States–Japan relations, with its 130 corporate members and nearly 2,000 individual members.