Japan's imperial couple has hosted a spring garden party in Tokyo. About 2,000 guests attended the event on Thursday.
The emperor and empress hold parties every spring and fall at the Akasaka Imperial Garden.
They spoke to guests while touring the garden with Crown Prince Naruhito, Prince and Princess Akishino and other imperial family members.
The guests included Kyoto University Professor Shinya Yamanaka, who won last year's Nobel Prize in Physiology or Medicine for his work on iPS cells.
Yamanaka told the emperor that he aims to introduce clinical applications of his research as soon as possible. The emperor said many patients must have high hopes for his work. Yamanaka said he will keep working hard to find treatments for diseases with no known cures.
The emperor also spoke to astronaut Akihiko Hoshide, who last year stayed on the International Space Station for 4 months.
Hoshide told the emperor about his activities and experiments during the mission. The emperor encouraged him to keep up the good work.