Prince Tomohito of Mikasa, a cousin of Emperor Akihito, was hospitalized Monday for suspected pericarditis, a heart ailment, at Keio University Hospital in Tokyo, the Imperial Household Agency said.
The 59-year-old prince had complained of slight chest pain, according to the agency. He is expected to be in the hospital for about three days, the agency said.
The prince drew attention last week when it became known he wrote in a privately circulated newsletter that he opposed the idea of allowing a female on the throne.
Late last month, a government panel on Imperial succession expressed support for legal revisions to allow a female on the Chrysanthemum Throne, a move that would break a centuries-old tradition of male-only succession.
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