A Christian who took to preaching and priesthood at the young age of 17, Yashiro devoted his life to religious activities around the world. In 1948 he was permitted to travel overseas as the first Japanese citizen after World War II to attend an international conference. During that trip he also hand-delivered a letter from Emperor Showa of Japan to George VI, the then King of England. He acted as a civilian diplomat while diplomatic relations between Japan and the rest of the world were cut off. His deeds are widely known and still held in high regard around the world today