Hundreds of North Korean fishing boats have washed up on Japan's shores in the last five years after fishermen got lost at sea and died.

Japanese media quoted maritime police as saying 227 North Korean fishing boats have washed up there since January 2013. One Japanese government official said, "We can't reveal the number of dead North Koreans who have been discovered considering diplomatic repercussions."

Yoshihiko Yamada at Tokai University, said the ghost ships wash up mostly in winter, when the wind blows from Siberia toward Japan.

Many more are believed to have been lost at sea, and very few fishermen reach Japanese shores alive. If they set off from the North Korean ports of Hamhung or Wonsan, they drift for 1,000 km over a period of more than two months before their vessel gets stranded on Japanese shores.

The reason seems to be that the North Korean regime ordered fishermen to drastically boost their catch, while local markets that have sprung up since 2012 have also increased economic pressure on fishermen to deliver goods to sell there.

Satoru Miyamoto at Seigakuin University told Japanese broadcaster NHK last year, "After the order to boost fish hauls, fishermen have been venturing recklessly into the ocean. These small wooden boats lack radar and GPS equipment, so if they run into bad weather on the high seas they end up being pushed to Japan by the currents."

