Prince Akishino and his wife Princess Kiko arrived in Hawaii on Monday for a six-day official visit to commemorate the 150th anniversary of Japanese immigration to the islands.

On the first day, the prince, the younger son of Emperor Akihito, and the princess laid a wreath at the National Memorial Cemetery of the Pacific, which commemorates U.S. soldiers who died during World War II and the Vietnam War, and visited two cenotaphs for Japanese immigrants.

They also visited a monument in Honolulu dedicated to nine people, including four high school students, who died in a 2001 collision off Oahu Island between the Ehime Maru, a Japanese fisheries school training boat, and a U.S. Navy submarine on a demonstration cruise that was carrying civilians.

The prince will be first in line to the throne after the accession of his elder brother, Crown Prince Naruhito, following the emperor's abdication on April 30, 2019.

During the couple's first official visit to the United States, Prince Akishino will deliver a speech Thursday at a ceremony to mark the arrival of the first group of Japanese immigrants in Hawaii in 1868.

In the afternoon, the couple visited Bernice Pauahi Bishop Museum, the state's largest museum, where the prince opened an exhibition on the first group of Japanese immigrants, known as Gannenmono, with around 200 of their descendants in attendance.

Nearly 150 Gannenmono emigrated from Japan in the first year of the Meiji era to settle across Hawaii, paving the way for the Japanese laborers to work on Hawaii's plantations, according to the museum.

The couple are scheduled to attend an event Wednesday organized by the Association of Nikkei and Japanese Abroad, a Yokohama-based organization connecting members of the Japanese diaspora with their ancestral homeland.

The prince and princess also met with people of Japanese descent during their visits to Brazil in 2015 and Chile last year.