About Prince Hisahito of Akishino
Prince Hisahito of Akishino (悠仁親王, Hisahito Shinnō; born 6 September 2006) is a member of the Imperial House of Japan. He is the youngest child and only son of Crown Prince Fumihito and Crown Princess Kiko, and the nephew of Emperor Naruhito. He is second in the line of succession to the Japanese throne behind his father. Preceding his birth, the paucity of male heirs in the imperial family had triggered the Japanese imperial succession debate, with some politicians favoring the abandonment of agnatic primogeniture which has prevailed in Japan since its monarchy was established, with eight exceptions (the last reigning empress being Go-Sakuramachi, r. 1762–1771), and which remains the law of imperial succession under the post-World War II constitution of Japan. The birth of Hisahito in 2006 removed the need to make any non-traditional provision for the succession. He became, at birth, next in the line of succession after his uncle and father. He was first seen in public on 15 September 2006, outside Aiiku Hospital. "Hisahito", the Prince's personal name, chosen by his father, means "serene and virtuous", according to the Imperial Household Agency.
Biography source: Wikipedia. The profile adds birthday-specific historical context from the Celebs Birthday Today editorial database.