Yumi Hiwatari was a Visiting Fellow at CIS in 2005–06. She is a Professor of International Relations at Sophia University in Tokyo and has written widely on U.S.-Japan relations and Japanese defense politics. Her current research interests concern the comprehensive review of Japan’s defense policy, especially the policy changes that took place during the Koizumi administration and their impact on Japan Self-Defense Forces. She has an essay on that topic in Breakthroughs, Spring 2006. In June 2010, she made a short speech for Japan Maritime Defense Force midshipmen and the U.S. Navy ROTC at the Maritime Officer Candidate School in Etajima, Japan. She also teaches at Japan Maritime Staff College.
In 2012, Hiwatari finally finished her book on Japan's national security. The book title is Defending Strategy: Rethinking Japan's National Security (Senshu Bouei Kokufuku no Senryaku). The publisher is Minerva Shobo Japan. The book consists of five chapters, including strategy, U.S.-Japan alliance, defense budget, structural reform, and civil-military relations. It is available only in Japanese.