After graduating the Department of Literature of University of Tokyo, he has filled important posts such as: head director of municipal library of Matsumoto city in Nagano prefecture, professor of Sagami Women's College, lecturer of University of Chiba.
Essentially, School of Ogasawara had been strictly monopolized by the Shogun, handed down from Ogasawara ancestors for generations. Therefore, their teachings were never taught to the commons. But Tadamune introduced the School of Ogasawara for the first time as the hereditary master to the public. He felt that absence of courtesy and discipline bring about demoralized mind and hoped to make good use of the general etiquette of the Ogasawara for the future as one of Japanese cultural assets beyond 800 years of long history, wishing the succession to the School of Ogasawara. To make good use of the soul of traditional etiquette in today's education, he enthusiastically started a lecturing activity nation wide and an educational activity to bring up etiquette instructors. And at times he also appeared on TV. His He died of acute pneumonia on May 10th ,1996 at the age of 76.