At the time, experts said the bodies on the boats could be those of refugees or fishermen, driven into more risky waters by desperation from North Korea's well-documented food shortages. In 2015, a dozen such ships were found in the last few months of the year.
According to CNN the unidentified "ghost ship" was spotted by the Akita Coast Guard drifting offshore Friday but it wasn't until it came into land that the grisly discovery was made. On Nov. 23, a boat washed up on the shores of Akita prefecture, and eight living North Koreans were rescued after they had been stranded with a squid catch. Empty packs of cigarettes and life vests both featured North Korean writing, and it seems clear that the ship hadn't simply gotten lost. Two days later, a boat was found with four bodies.
Due to North Korea's secretive nature, it's not exactly like Japanese authorities can reach out to them for help in identifying the men or notifying their families, so this sad story might never have a final chapter.
While officials would not confirm the boat was from North Korea, it matches a spate of vessels and debris that have ended up on Japan's west coast. In recent years, a number of ships have washed up there.
The so-called North Korean ghost ships are not something new for Japan.
As overfishing continues in the waters near North Korea, and as the food shortages in the country show no signs of stopping, it's likely that these types of disasters will become even more common. The most likely explanation is that the men were refugees hoping to escape North Korea only to meet their untimely demise in the Sea of Japan.
The sunken boat was detected by sonar equipment about 40 meters from the area where it had been moored. Defectors have arrived through this route but experts believe the victims were not civilians attempting to leave the country.
Satoru Miyamoto, a professor at Seigakuin University and expert on North Korea told CNN: "It's after Kim Jong Un chose to expand the fisheries industry as a way of increasing revenue for the military".
Experts say some of these boats are carrying soldiers who know nothing about fishing or navigation. "I was surprised to see the boat in such a bad condition", she said.