Thanks for that link. Good read. It still looks like the charges at the war crimes tribunal in 1946 didn’t focus on the actual improper marking of the ship though. That’s why the captain was not in the trial. I’d be interested if there is an actual case where the captain was charged with violating article 46 of the Geneva Convention.
Not that I’m aware of. The Japanese were so brutal that even significant war crimes were ignored after the war.