Japan's Emperor Naruhito and Empress Masako wave to well-wishers during their royal parade to mark the enthronement of Japanese Emperor Naruhito in Tokyo, Japan November 10, 2019. They rode through central Tokyo on Sunday in a motorcade to mark this year's imperial succession as well-wishers waved national flags and held up mobile phones for snapshots of the smiling royal couple. REUTERS/Kim Kyung-Hoon

Japan's Emperor Naruhito and Empress Masako wave to well-wishers during their royal parade to mark the enthronement of Japanese Emperor Naruhito in Tokyo, Japan November 10, 2019. Emperor Naruhito, 59, acceded to the throne in May after his father, Akihito, became the first monarch to abdicate in two centuries. REUTERS/Kim Kyung-Hoon

Japan's Emperor Naruhito and Empress Masako wave to well-wishers during their royal parade to mark the enthronement of Japanese Emperor Naruhito in Tokyo, Japan November 10, 2019. The parade was originally due to take place on Oct. 22, when the emperor officially proclaimed his enthronement before dignitaries from about 190 countries, but it was postponed as Japan grappled with the aftermath of a devastating typhoon. REUTERS/Kim Hong-Ji

Japan's Emperor Naruhito and Empress Masako wave to well-wishers during their royal parade to mark the enthronement of Japanese Emperor Naruhito in Tokyo, Japan November 10, 2019. Under a cloudless blue sky, Emperor Naruhito and Empress Masako, Harvard-educated former diplomat, waved from an open-top Toyota Century limousine, which cruised through streets lined with spectators and police. REUTERS/Kim Kyung-Hoon

Japan's Emperor Naruhito and Empress Masako ride in a car during their royal parade to mark the enthronement of Japanese Emperor Naruhito in Tokyo, Japan November 10, 2019. The emperor wore a tailcoat and Empress Masako a white dress and a tiara that sparkled in the sunshine. It was a stark contrast from last month's enthronement ceremony, in which both wore traditional robes. REUTERS/Kim Kyung-Hoon

Japan's Emperor Naruhito and Empress Masako ride in a car during their royal parade to mark the enthronement of Japanese Emperor Naruhito in Tokyo, Japan, November 10, 2019. Empress Masako appeared moved. Japanese media reported she appeared to wipe away an emotional tear during the 4.6-kilometre (2.9 miles) ride. Tens of thousands of spectators from across the country gathered along the route, which was packed many rows deep with cheering, flag-waving well-wishers. Kyodo/via REUTERS