"Attention all hands: Anyone on board have katana and piece of rice paper?"
It would be premature for the Japanese Captain to plan his seppuku. He is not guilty, the Korean Captain is. There is a hole in the right side of the Korean freighter. According to Wikipedia:
Consider two ships on courses that intersect. The rule is that the ship on the left must give way.
Korean ship was on the left, and it failed to yield. Compare with the identical case of Andrea Doria.