The UNESCO World Heritage committee on Saturday decided to register Japan’s controversial Sado gold mine as a cultural heritage site after the country agreed to include it in an exhibit of its dark history of abusing Korean laborers during World War II.

The decision signals an improvement in ties between Tokyo and Seoul.

The mine on an island off the coast of Niigata in northern Japan operated for nearly 400 years and was once the world’s largest gold producer before closing in 1989. It…