A gold and silver mine site recommended by the Japanese government for UNESCO World Heritage but opposed by South Korea will not be considered for inclusion in the 2023 list after the U.N. agency found the application was incomplete, officials said Thursday.

Japanese education minister Shinsuke Suematsu said the situation is "difficult" after the U.N. Educational, Scientific and Cultural Organization chose not to forward the recommendation for the mine on Niigata Prefecture's Sado Island to its advisory body by the deadline for review for next year's registration.

The mine is regarded as one of the world's largest producers of gold in the 17th century and is known for its pre- and post-industrialization technology.

Japan's recommendation for the mine in February for the 2023 UNESCO World Heritage list drew protest from South Korea, which claims the site is linked to the wartime forced labor of Koreans.

File photo taken in August 2021 shows a relic of opencast mining on Sado Island. (Kyodo)

UNESCO has expressed concern to Japan about the conflict between the two countries over historical issues spilling over into the World Heritage Committee, according to sources familiar with the matter.

On the organization's choice not to forward the application, Suematsu said, "UNESCO indicated to us that it decided part of the recommendation was not sufficient."

But he backed the documentation provided, saying, "There was no issue with the explanations from the Japanese side, and I'm confident they were correct. It (reapplying) is a tough choice."

The Japanese government plans to reattempt to register the site in 2024 or later, according to the officials.

While each country recommends its own sites for World Heritage registration by February each year, UNESCO's working guidelines stipulate that recommendations must be forwarded to its advisory body by March 1 for review.

If all goes as planned, the advisory body surveys the site to determine whether it is worthy of being added to the list. The World Heritage Committee makes a formal decision around summer each year.

The committee was scheduled to meet in Russia this year, but the meeting was postponed due to the war in Ukraine. It remains unknown where or when the next meeting will be held.

Despite the uncertainty, Deputy Chief Cabinet Secretary Yoshihiko Isozaki said the government "is aiming to register as quickly as possible." A preliminary edition of the recommendation is planned to be completed by the end of September, with an official version to be conveyed to UNESCO by Feb. 1 2023.

Japan's Council for Cultural Affairs selected Sado mine as a candidate last December, but the government had considered delaying its plan to recommend the mine in the face of opposition from South Korea.

South Korea has been urging Japan not to pursue the listing because of what Seoul views as the forced labor of Koreans on the island during Japan's 1910-1945 colonization of the Korean Peninsula.

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