Emperor Akihito, in his last appearance as reigning monarch at an annual ceremony marking Japan's World War II surrender, has expressed "deep remorse" over the conflict.
Prime Minister Shinzo Abe, meanwhile, on Wednesday vowed never to repeat the horrors of war.
Earlier Abe sent a ritual offering to Tokyo's controversial Yasukuni Shrine for war dead, but did not visit in person out of apparent consideration for ties with Seoul and Beijing.
Past visits by Japanese leaders to Yasukuni have outraged China and South Korea because the shrine honours 14 Japanese wartime leaders convicted as war criminals by an Allied tribunal, along with war dead.
China's relations with Japan have long been haunted by what Beijing sees as Tokyo's failure to atone for its occupation of parts of China before and during WWII, although ties have thawed recently.
Japan occupied Korea from 1910-1945 and bitter memories still rankle.
"Thinking of the peaceful times that have extended for many years after the war, reflecting on our past and with a feeling of deep remorse, I earnestly hope that the ravages of war will never be repeated," Akihito, wearing morning dress and accompanied by a kimono-clad Empress Michiko, said at the ceremony for war dead.
Akihito, 84, who will abdicate next year, has carved out a role as a symbol of peace, democracy and reconciliation during his three decades on the throne, visiting wartime battlefields to pray for war dead of all nationalities.
His remarks on Wednesday echoed those he first spoke on the 70th anniversary of the war's end, in a subtle departure from previous comments that were seen by many liberals and moderate conservatives as a subtle rebuke to Abe.
The prime minister has said future generations of Japanese should not have to keep apologising for the conflict.
On Wednesday, Abe vowed never to repeat the horrors of war.
"I will humbly face the past and resolutely uphold this promise," he said.
Separately, a group of about 50 conservative Japanese lawmakers including Shinjiro Koizumi, the popular son of former prime minister Junichiro Koizumi who is often spoken of as a future premier, paid their respects at Yasukuni.
Ruling Liberal Democratic Party lawmaker Masahiko Shibayama, who made the offering at Yasukuni on Abe's behalf, said the prime minister asked him to pray for the souls of the departed and that Abe regretted being unable to pay his respects in person.
Abe has only visited the shrine in person once since taking office in 2012.
Australian Associated Press
