Sharjah24 - AFP: Under a split-top mountain on the Japanese island of Sado lies a network of centuries-old mines that have sparked a new diplomatic row with South Korea.

Some of the gold and silver mines of Sado, off Japan's west coast, are believed to have started operating as early as the 12th century and produced until after World War II.

Japan believes that lengthy history and the artisanal mining techniques used there at a time when European mines had turned to mechanisation merit recognition on UNESCO's World Heritage List.

But in Seoul, the focus is on what isn't mentioned in the bid: the use of conscripted Korean labour during the Second World War, when Japan occupied the Korean peninsula.

Japan is seeking recognition of three sites -- the Nishimikawa gold mine, the Tsurushi silver mine, and the Aikawa gold and silver mines -- for the period between 1603 and 1867.

Officials and supporters of the bid say that era was when the mines were the world's most productive and mining was done by hand.

But it also stops short of the period when conscripted Koreans toiled in conditions that even some backers of the UNESCO bid call "extremely harsh".

The World Heritage effort has been years in the making, inspired in part by the successful recognition of a silver mine in western Japan's Shimane region.

Ryo Usami, from Sado city's World Heritage Promotion section, said locals hoped the recognition would highlight the mine's contributions to the unique culture and history of the island.

"Many people migrated to Sado to mine gold and silver... They came from all over Japan and brought their local cultures," Usami said .

"Sado's history is basically the history of these gold mines, and its culture formed in part thanks to the mining operations. That's what Sado city wants to preserve."