Japan's Emperor Akihito has said the practice of mourning Japan's war dead can help younger generations better understand the past.
The emperor celebrated his 73rd birthday on Saturday
He said he hoped facts about World War II would be correctly conveyed so the suffering his generation experienced would never be repeated.
The emperor's comments came in a speech marking his 73rd birthday.
Correspondents say teaching Japan's wartime history and remembering the war dead is still highly controversial.
"Now that the number of those who were born after the war increases as years pass by, the practice of mourning the war dead will help them to understand what kind of world and society those in the previous generations lived in," Emperor Akihito said, in remarks made on Wednesday, but only made public on Saturday.
"I sincerely hope that the facts about the war and the war dead will continue to be correctly conveyed to those of the generations that do not have direct knowledge of the war so the kind of ravage of war that we experienced in the past will never be repeated," he added.
Built in 1869 to honour victims of the Boshin Civil War
Now venerates the souls of 2.5m of Japan's war dead
Those enshrined include 14 Class A war criminals
However, the emperor avoided touching on how people should honour those who died in World War II.
He made no mention of the Yasukuni shrine, which honours 2.5 million war dead, including 14 people convicted as criminals by a 1948 war tribunal.
Many of Japan's neighbours believe the shrine glorifies Japan's militaristic past, and that visits by the country's leaders show the country has yet to fully face up to past atrocities.
Repeated visits by former Japanese Prime Minister Junichiro Koizumi severely strained relations with China and South Korea in recent years.
Japan's new Prime Minister Shinzo Abe has not said if he plans to visit Yasukuni himself.