The young man on course to be Japan’s future emperor is attracting the attention of the country’s voracious media, with rumours of girlfriends and security challenges as a university student, and hints of unrest in the palace over succession. Royalists say the media should leave 19-year-old Prince Hisahito alone to concentrate on his environmental studies course at the University of Tsukuba, while a debate mounts on whether the constitution should be altered to allow his cousin to become Japan’s...