The 83-year-old Akihito and his wife, Michiko, are on their first visit to the country, the latest in a series of trips to former battlegrounds.
"It is our hope that our visit to Vietnam will contribute to the further development of the mutual understanding and friendly relations between our two countries," Mr. Akihito said earlier at Tokyo's Haneda Airport.
Akihito and Michiko are scheduled to visit Hanoi and the former imperial capital of Hue, according to the official program.
The JiJi Press said a government jet carrying the Imperial couple took off from Tokyo International Airport at Haneda in the morning and arrived at an airport in Hanoi, the capital of the Southeast Asian nation, in the afternoon. This is the first visit to Vietnam by the Emperor and the Empress, and also their first overseas trip since they made an official visit to the Philippines in January 2016.
The South China Morning Post reported that Japan’s emperor arrived in Vietnam on Tuesday for a whirlwind tour that will include a meeting with families of Japanese soldiers who stayed there after the second world war.
The emperor and empress were received by Vice President Dang Thi Ngoc Thinh and guards of honor at the Hanoi airport, where national flags were displayed.
According to AP, today, Japan is Vietnam's biggest foreign donor and one of its top investors and trading partners.
The two countries have enjoyed closer military and security ties in recent years.
The Emperor's visit follows one by Japanese Prime Minister in January, during which he pledged to provide Vietnam with new patrol vessels.
Japan's Asahi Shimbun reported that the Emperor and Empress would meet Nguyen Duc, 36, who was born conjoined to his brother, Viet. Their condition is believed to have been caused by the effects of Agent Orange and other herbicides sprayed over the country by US forces during the Vietnam War.
The twins received treatment in Japan in 1986 and were surgically separated in 1988 under the care of Japanese and Vietnamese doctors./.