In June 2005, the Emperor Akihito and the Empress Michiko visited the island of Saipan (part of the Northern Mariana Islands, a U.S. territory), the site of a battle in the World War II from 15 June to 9 July 1944 (known as the Battle of Saipan). Accompanied by Empress Michiko, he offered prayers and flowers at several memorials, honoring not only the Japanese who died, but also American soldiers, Korean labourers, and local islanders. It was the first trip by a Japanese monarch to a World War II battlefield abroad. The Saipan journey was received with high praise by the Japanese people, as were the Emperor's visits to war memorials in Tokyo, Hiroshima Prefecture, Nagasaki Prefecture and Okinawa Prefecture in 1995.
In extension of his father's interest in marine biology, who published taxonomic works on the Hydrozoa, the Emperor Emeritus is a published ichthyological researcher, and has specialized in studies within the taxonomy of the family Gobiidae. He has written papers for scholarly journals such as Gene, Ichthyological Research, and the Japanese Journal of Ichthyology. He has also written papers about the history of science during the Edo and Meiji eras, which were published in Science and Nature. In 2005, a newly described goby was named Exyrias akihito in his honour, and in 2007 a genus Akihito of gobies native to Vanuatu also received his name.