Crown Princess Kiko marked her 58th birthday on Sept. 11 with a statement expressing concern about the ongoing online criticism of her family and sharing her hopes for her only son, Prince Hisahito.

Kiko also mentioned her son, Prince Hisahito, and the family's plans to sit down together to discuss which high school he should attend. Hisahito, 14, second in line to the throne, is a second ...