Japan's Imperial Household Agency says Emperor Akihito has been hospitalized for tests.
An agency official says that the 78-year-old Akihito was admitted to University of Tokyo Hospital on Saturday for testing, but that the visit was not an emergency.
Akihito has had various health problems in recent years, including pneumonia and prostate cancer. He has cut back on public duties but appears relatively healthy.
According to Kyodo News agency, the emperor will get tests for his heart, which may be suffering from a deficient blood supply.
AP