Twelve fishermen were missing on Thursday following a crash between a Brightoil tanker and a trawler.
The Jiji website said the Chinese fishing vessel, Lurong Yuanyu 378, and the 115,000-dwt aframax Brightoil Lucky (built 2009) were in collision in the Sea of Japan off Shimane, citing the coast guard.
The trawler, which had a crew of 16, overturned in the incident.
