A growing number of North Korean fishing boats are washing up on the shores of Japan.

Sometimes there are survivors but often they carry a tragic cargo of corpses from the so-called "Hermit Kingdom".

Shizuo Sato recalls the day he made a grim discovery on Japan's west coast.

"We've known of many ghost ships found in this area," he says. "We all thought that if it's a dead body, it must be a North Korean."

These mysterious "ghost ships" are a diplomatic, logistical and financial nightmare for Japan, costing millions of dollars in police investigations, clean-up operations and repatriation of survivors and human remains.

In December 2017, eight North Korean fishermen washed up dead on Japan's Oga peninsula.

The remains of the fishermen are still in limbo. For now, they are being kept at a temple by a local monk, Ryosen Kojima.

"The eight bodies were cremated and the ashes are temporarily kept here," says Ryosen. "I imagine the crews died with unimaginable fear."

While analysts debate what the ghost ships may reveal about the secretive nation, in Japan, the shipwrecks remind some of a dark past when North Korean spies abducted Japanese citizens.

"We've been warned not to get too close to North Korean ships, as they might do something bad to us," says Ken Honma, a fisherman who spends nine months of each year in a fishing zone about 500 kilometres (311 miles) from the North Korean port city of Chongjin.

101 East investigates North Korea's ghost ships.

Source: Al Jazeera News