Japan's Emperor Akihito pledged on Tuesday to honor those who died in one of World War II's deadliest battles, as he began a historic visit to the Philippines. Akihito, 82, and his wife, Empress Michiko, 81, will visit two war memorials during the five-day trip, the first by a reigning Japanese emperor to the Southeast Asian nation. "In the Philippines, many lives of Filipinos, Americans and Japanese were lost during the war," Akihito said at a ceremony before leaving Tokyo. Akihito specifically noted the battle for the liberation of Manila in 1945, where an estimated 100,000 people were killed. "We'd like to conduct our visit by always keeping this in mind," he said. As soon as Akihito stepped out of the plane at Manila's airport, he offered a slight bow. He was then welcomed on the tarmac by President Benigno Aquino and many of his Cabinet secretaries. The Philippines is the latest stop in the soft-spoken emperor's pacifist pilgrimage, which has appeared to contradict his government's nationalist bent. The emperor and empress have previously journeyed to other Pacific battle sites where Japanese troops and civilians made desperate last stands in the name of wartime emperor Hirohito, Akihito's father. On visits to Saipan in 2005 and Palau last year they prayed not just for the Japanese soldiers and civilians who perished, but also colonial subjects and troops from its wartime enemy, the United States. In remarks at a memorial marking the 70th anniversary of Japan's 1945 surrender, Akihito expressed "profound remorse" for the war fought in his father's name, reportedly the first time he used those words at the annual event. Akihito was 11 years old when the war ended with the obliteration of Hiroshima and Nagasaki. In the Philippines the couple will pay their respects at separate memorials for Filipino and Japanese WWII casualties. They will also visit a Japanese language training centre and the International Rice Research Institute. Japan's brutal three-year occupation of the Philippines ended in 1945 after the Americans liberated their former colony in a daring sea battle. The two nations have steadily built closer ties, with Japan the Philippines' biggest source of foreign investment and aid. Akihito's trip is being held to celebrate 60 years of diplomatic relations. The two nations have also drawn closer in recent years as they have struggled to deal with similar territorial rivalries with China. However not everyone in the Philippines has welcomed the closer ties. Filipina women who were forced into sexual slavery by the Japanese military have vowed to hold protests in Manila during Akihito's visit. They believe the Japanese government has never made a sincere apology or offered adequate compensation for the war crimes.