During the Liberation War, Ken Arimitsu was a student leader of Waseda University of Japan and the Deputy Secretary General of Japan Solidarity Committee (Tokyo group) for Bangladesh. He tirelessly worked to create public opinion in favour of Bangladesh and organized a number of fund raising and awareness events. The members of their group supported the Bangalee staff members of the Pakistan Embassy and the Bangalee university students in Tokyo who denounced Pakistan nationality. He also set up another organization named 'Lets act as brothers and sisters of the People of East Bengal', through which he appealed to the student community of Japan to support the cause of Bangladesh. For his great contribution to the Liberation War of Bangladesh, Ken Arimitsu is awarded Friends of Liberation War Honour.