By Sakura Murakami

TOKYO Japanese Emperor Naruhito on Thursday said working with developing countries will be key to solving global issues like climate change, as he prepared to travel to Indonesia on his first state visit since his enthronement in 2019.

He also acknowledged the "difficult time" in relations with the country in an apparent reference to Japan's wartime occupation of the Dutch West Indies.

Naruhito, the grandson of Emperor Hirohito in whose name Japan fought World War Two, is Japan's first monarch born after the war. He will be joined on the trip to Indonesia by his wife, Empress Masako.

"Working with new and developing countries is becoming increasingly important to resolve global issues such as climate change, energy, and food," he said at a news conference held at the Imperial Palace in Tokyo.

Noting that this year marks 50 years of relations between Japan and the Southeast Asian bloc ASEAN, he said he hoped to see a further deepening of ties between Japan and ASEAN chair Indonesia as he embarks on his tour from Saturday.

At the press conference, Naruhito spoke of hearing about his parents' wartime experiences and said that he would inherit their dedication to peace.

"There was a difficult time in our relations with Indonesia," Naruhito said, adding that his heart hurt when he thinks of the many lives lost and the suffering and pain of the war.

Indonesia, then a Dutch colony, was controlled by Japanese forces between 1942 and the end of the war in August, 1945. It declared independence days after the conflict ended.

"I think it's important to nurture a love of peace, as we deepen our understanding of history without forgetting those who passed," he said.

(Reporting by Sakura Murakami; Editing by Conor Humphries)