Japanese Prince Akishino and Princess Kiko Visits Hawaii on June 4, 2018

Princess Kiko of Akishino attends the Anti-Tuberculosis Association Meeting on May 31, 2018, in Tokyo, Japan.

Princess Kiko of Akishino delivers a speech during the Anti-Tuberculosis Association Meeting on May 31, 2018, in Toky,o, Japan.

Princess Kiko of Akishino attends the Anti-Tuberculosis Association Meeting on May 31, 2018, in Tokyo, Japan.

Japan's Prince Akishino (C) and Princess Kiko arrive to pay their respects at the Ehime Maru Memorial in Kaka'ako Park in Honolulu, Hawaii on June 4, 2018. - The Ehime Maru was a Japanese fishery high-school training vessel that was struck accidentally by the USS Greeneville submarine during a demonstrative maneuver in 2001.

Japanese Prince Akishino (L) and his wife Princess Kiko (C) visit on June 4, 2018, a monument in Honolulu dedicated to nine people who died in a 2001 collision off Oahu Island between the Japanese fisheries school training boat Ehime Maru and a U.S. naval submarine.

Japanese Prince Akishino (3rd from R) and his wife Princess Kiko visit on June 4, 2018, a monument in Honolulu dedicated to nine people who died in a 2001 collision off Oahu Island between the Japanese fisheries school training boat Ehime Maru and a U.S. naval submarine.

Japanese Prince Akishino (L) and his wife Princess Kiko observe a moment of silence in Honolulu on June 4, 2018, in front of a monument dedicated to nine people who died in a 2001 collision off Oahu Island between the Japanese fisheries school training boat Ehime Maru and the U.S.

Japanese Prince Akishino (2nd from L) and his wife Princess Kiko (2nd from R) visit on June 4, 2018, a monument in Honolulu dedicated to nine people who died in a 2001 collision off Oahu Island between the Japanese fisheries school training boat Ehime Maru and a U.S. naval submarine.

Japanese Prince Akishino (2nd from L) and his wife Princess Kiko (2nd from R) visit on June 4, 2018, a monument in Honolulu dedicated to nine people who died in a 2001 collision off Oahu Island between the Japanese fisheries school training boat Ehime Maru and a U.S. naval submarine.

Japanese Prince Akishino (L) and his wife Princess Kiko (2nd from R) visit the National Memorial Cemetery of the Pacific in Honolulu, which commemorates soldiers who died during World War II and the Vietnam War, on June 4, 2018.

Japanese Prince Akishino (5th from L), alongside his wife Princess Kiko (3rd from L), signs a guestbook after paying tribute at the National Memorial Cemetery of the Pacific in Honolulu, which commemorates soldiers who died during World War II and the Vietnam War, on June 4, 2018.

Japanese Prince Akishino (L), Honolulu Mayor Kirk Caldwell (center) and Princess Kiko plants a tree at Thomas Square Park in Honolulu, HI, Tuesday, June 5, 2018, during his visit to the island of Oahu. The prince and princess of Japan are in Hawaii this week to mark the 150th anniversary of Japanese immigration to the Hawaiian islands.

Prince Akishino of Japan and his wife Princess Kiko arrive for a tree planting ceremony at Thomas Square Park in Honolulu, Hawaii, on June 5, 2018, during their visit to the island of Oahu.

Prince Akishino of Japan attends tree planting ceremony at Thomas Square Park in Honolulu, Hawaii, on June 5, 2018, during their visit to the island of Oahu. - The prince and princess of Japan are in Hawaii to mark the 150th anniversary of Japanese immigration to the Hawaiian islands.

(FromL) Prince Akishino of Japan, Honolulu Mayor Kirk Caldwell and Princess Kiko of Japan plant a tree at Thomas Square Park in Honolulu, Hawaii, on June 5, 2018, during their visit to the island of Oahu.

Japanese Prince Akishino (L) and his wife Princess Kiko (C) watch a Japanese drumming performance by local children at the Japanese Cultural Center of Hawaii in Honolulu on June 5, 2018.

Japanese Prince Akishino (2nd from L) and his wife Princess Kiko (L) look in on a kendo Japanese martial art lesson at the Japanese Cultural Center of Hawaii in Honolulu on June 5, 2018.

Japanese Prince Akishino (C) and his wife Princess Kiko (L) visit the Japanese Cultural Center of Hawaii in Honolulu on June 5, 2018.

Japanese Prince Akishino (2nd from L) and his wife Princess Kiko (L) look in on a kendo Japanese martial art lesson at the Japanese Cultural Center of Hawaii in Honolulu on June 5, 2018.

Japanese Prince Akishino (2nd from R) and his wife Princess Kiko (3rd from R) head to a tree-planting ceremony in Honolulu on June 5, 2018.

Prince Akishino of Japan attends tree planting ceremony at Thomas Square Park in Honolulu, Hawaii, on June 5, 2018, during their visit to the island of Oahu.

Japanese Prince Akishino delivers a speech at the opening ceremony of the 59th Convention of Nikkei and Japanese Abroad in Honolulu on June 6, 2018. His wife Princess Kiko (back) also attended the ceremony.