Nine of the 12 crewmembers from the Japanese freighter have been rescued, and the coast guard was searching for others in waters roughly 4 kilometers (2.5 miles) north of the coast of Imabari in Ehime prefecture.
The Byakko collided Thursday night with a chemical tanker operated by a South Korean company, and the collision caused the Byakko to sink.
Ulsan Pioneer tanker was run by South Korean firm Heung-A Shipping Co. with 13 crew members, including Korean and Myanmar nationals, the coast guard said in a statement. It departed a port in China on Tuesday for Osaka, Japan, conveying acetic acid.
None of the Ulsan Pioneer’s crew members was injured.
The Byakko was operated by Kobe-based Prince Kaiun Co. and was carrying car parts overnight to Kanda, a town in Fukuoka prefecture.
On average, around 400 vessels a day pass through the Kurushima Strait in southern Japan where the collision occurred.