A college professor has sent to officials of 21 UNESCO member states a video that details the truth about a coal mine on Hashima Island in Japan, which Tokyo is seeking to have included on the UNESCO World Heritage List.

Seo Kyung-duk, a professor at Sungshin Women's University, said he also posted the video titled "The Truth of Hashima" on the content sharing site You Tube.

The three-minute video exposes the brutality of the forced labor suffered by coal miners recruited from countries like Korea and China on the island during World War II.

Professor Seo said he made the video so viewers around the world could easily grasp the historical facts and also compared it with Germany's Zollverein Coal Mine which earned world heritage status after acknowledging the site's history of forced labor.

Seo said he wanted to convey the truth about Hashima Island to the UNESCO World Heritage Committee members that will be voting on Japan's bid.

The Tokyo government has applied for world heritage status for 23 industrial sites in the Kyushu region including the Hashima coal mine. The committee will announce its decision after its meeting later this month.