The defense official said the Japanese ship's bow was badly burned and mangled, but the vessel was still capable of traveling on its own. The container ship's hull was grazed near its bow.
it could be both ship's fault. Both ships are obligated to maneuver in a meeting situation.
That said, from what I know of the straits a meeting situation is not common. Because of the currents traffic is generally one-way through the straits-stemming the current. Down stream traffic is discouraged and maybe even prohibited, I can't remember for sure.
Well, most collisions require a mix of fault on the part of both ships.
Wakes visible on satellite images of the area indicate lots of traffic -- going in both directions simultaneously.