In this photo taken on Aug. 18, 2010 and released by Japan's Imperial Household Agency on Monday, Sept. 6, 2010, Japanese Prince Hisahito, center, poses with his family members, father Prince Akishino, right, mother Princess Kiko, left, and sister Princesses, Mako, back row right, and Kako, for a family portrait at an imperial villa at Nasu in Tochigi prefecture, north of Tokyo. Hisahito celebrated his fourth birthday on Monday. [Xinhua/AFP