Nippon Mitsubishi Oil Corp. will export heavy oil to China under a one-year contract beginning in June, making it the first Japanese oil company to export oil products to China under a term contract, a company official said Monday.

Under the contract, Nippon Mitsubishi will export a total of 250,000 kiloliters of fuel oil C to major petroleum firm China National United Oil (China Oil), which handles import and export trade for the state-run China National Petroleum Corp., the official said.

Japan's sluggish economy has left it burdened with an excess supply of fuel oil C, which is used at power plants.

Nippon Mitsubishi exported 100,000 kiloliters of fuel oil C to China Oil in January under a spot contract.