On a desolate stretch of Japan's north-western coast lies a wrecked, wooden fishing boat with weather-beaten Korean characters near the bow.

Key points: 'Ghost ships' are so named because they often appear on beaches empty, or only with skeletal remains

'Ghost ships' are so named because they often appear on beaches empty, or only with skeletal remains In the last year 104 boats believed from North Korea have washed ashore in Japan

In the last year 104 boats believed from North Korea have washed ashore in Japan Old wooden boats started being used for fishing amid pressure from Kim Jong-un to expand the fisheries industry

A spider was the only living thing left on board, making a web between frayed ropes and a rusty engine.

Half-filled with sand, the boat sits amid slashed ropes, nets and other fishing equipment strewn on the beach.

It floated here and ran aground, empty, in February this year.

Who was on board or what actually happened before it ran aground, nobody knows.

Slightly further north, two bodies also washed ashore around the same time, but no-one can say for sure if they came from this boat.

Not far from the wreckage, local fisherman Hiroshi Hatakeyama looks over the sandy shore at an increasingly familiar sight.

Local fisherman Hiroshi Hatakeyama scans his hometown horizon with a sense of foreboding. ( ABC News: Jake Sturmer )

"I didn't feel good when I saw the boats, I thought — another one has come again? Another one?" he said.

In the last year alone, 104 boats believed to be from North Korea have washed ashore in Japan.

Many arrived here in Akita Prefecture.

A spider is the only sign of life onboard a fishing boat that ran aground empty in Japan in February. ( ABC News: Jake Sturmer )

They're called ghost ships, because they often appear on beaches empty, or with only the skeletal remains of their former pilots on board.

In January, one of the worst cases saw eight suspected North Korean bodies washed up from a wrecked ship in central Japan.

The badly decomposing bodies were found with a badge of North Korean founder Kim Il-sung and former leader Kim Jong-il, and a cigarette box with Korean characters.

Buddhist priest Ryosen Kojima's 470-year-old temple overlooks the sea in the Oga peninsula.

Buddhist priest Ryosen Kojima brings dignity to the remains of the people who cannot be identified. ( ABC News: Yumi Asada )

Inside the building, dozens of boxes contain the cremated remains of people who cannot be identified.

Priest Kojima lights two candles and then kneels before them; he begins chanting, reciting sutras to bring peace to their souls.

White boxes in the temple contain the remains of 10 North Korean fishermen whose bodies washed up last year in Oga peninsula. ( ABC News: Yumi Asada )

There are 10 white boxes, containing the remains of 10 North Korean fishermen whose bodies washed up last year.

"I imagine they felt loneliness and fear," Priest Kojima said.

"There were ten of them and they don't all die together.

"For example, one might have died … and then another died during the dark night and then another one died …

"They die one at a time, so I imagine there was tremendous fear."

Priest Kojima prays for peace for the their souls. ( ABC News: Yumi Asada )

He feels sorry they cannot return home or receive a funeral for the religion in which they believe.

"Perhaps rather than returning to North Korea, I could give a better prayer for their souls here," he said.

"If they're here, at least I can read a sutra for them and eventually they can go into a proper grave together."

The reason ghost ships keep washing ashore in Japan has sparked many theories, including speculation about North Korean attempts to infiltrate the country with spies.

It's not unfounded.

The reason ghost ships keep arriving in Japan has sparked many theories. ( ABC News: Yumi Asada )

In 1981 a policeman patrolling Oga City — not far from where several ghost ships have washed ashore — spotted three men getting out of a boat.

Two got away but one — an ethnic Korean born and raised in Japan — was arrested.

It turned out he was returning from North Korea after training as a spy.

But the increase in boats is likely a result of desperation by fishermen driven to dangerous lengths by an economically crippled regime.

"Those boats are not spy boats — spy boats need to be well equipped and it won't be wrecked by some storms," Seigakuin University Professor Satoru Miyamoto said

"If they get in trouble, Japan could find out about all their equipment.

"Most of the boats that were washed away this time were wooden boats and not well equipped so there is hardly any chance they were spy boats.

"Of course, you can't deny spy boats weren't mixed among them, but it's unthinkable when you consider the miserable fate of the old wooden ships.

"If they were spy boats they would sneak in during the night."

Amid pressure from North Korean leader Kim Jong-un to expand the fisheries industry, quotas were increased and the rogue state began to rely more and more on old wooden boats for fishing.

When the fishing industry expanded, farmers started to become fishermen.

Increased fishing quotas in North Korea saw many farmers turn to fishing using old boats. ( ABC News: Jake Sturmer )

"They risk their lives to catch fish so they can earn more money," Professor Miyamoto said.

"But as they're farmers they're not very used to the sea.

"When they actually went out they were in distress and there were a series of accidents."

But not all fishermen die during their journey.

In November last year, police in Akita received a call about eight suspicious men standing around the seaside in Yurihonjo.

They turned out to be North Korean fishermen whose boat had broken down.

Local media reported that the men told investigators they were not defectors and wished to return home.

With international sanctions tightening, the opportunities for North Korea to sell its fish become slimmer.

'Unlikely' to be North Korean spies

Professor Miyamoto said UN sanctions preventing countries from importing North Korean seafood will see the number of boats fall.

It remains to be seen whether the lack of market for North Korea to sell its fish will affect the number of crews risking the dangerous task.

The number of ships washing ashore has slowed in the last few months, but the squid fishing season is only now restarting for the year.

Already the Japan Coast Guard has had to warn 112 North Korean ships that have entered Japan's waters.

The Japan Coast Guard has had to warn an increasing number of North Korean boats in the past few months. ( Supplied: Japan Coast Guard )

Fear lies below local festivities

At Sakata port, on Japan's western coast, the start of squid fishing season is being marked with much fanfare.

Musicians beat taiko drums, mascots dance and geishas perform for the crowd.

A monk intones a blessing for the ships' captains and crews, as nervous mothers, fathers, wives and girlfriends watch on.

But this year their attention is on what's above the surface just as much as what's below.

The Yamato bank, around 400km from Japan's coast, is one of the region's most productive squid-fishing areas.

It's also fast becoming one of the most dangerous.

Ken Honma has captained his ship for the last 35 years — and he's very concerned about confrontations with North Korean boats illegally fishing in Japan's waters.

Squid fishing captain Ken Honma worries about confrontations with North Korean boats fishing illegally in Japan's waters. ( ABC News: Jake Sturmer )

"There are so many boats, it's hard to dodge them," he said.

"If it's day time we can at least see them, but they run without any lights at night time so they're very dangerous."

Last year alone Japan's coast guard spotted and warned almost 2,000 North Korean boats in Japanese waters.

Japan Coast Guard warns a ship that has entered Japan's waters using a large water spray, picture supplied by Japan Coast Guard, June 2018. ( Supplied: Japan Coast Guard )

One boat from the rogue state pointed a rifle towards a government ship, escalating an already tense situation.

"It's hard to operate my boat," Captain Honma said.

"I have to do business while fearing my physical safety — I can't even go to sleep.

"They come right near my boat and use a net so I worry that they'll do something to my boat or get on board."

Fishing families hope for stability from Trump-Kim summit

Locals tie streamers to the boats as they depart, leaving a colourful trail as they head out to sea.

As the captains blow their horns, the crowds wave farewell and wish them good luck. Some shed a tear.

They could be away for as long as 6 months, and in that time they're hoping for some kind of peaceful resolution with the North Koreans.

This week Donald Trump and Kim Jong-un will meet in a historic summit in Singapore aimed at bringing peace to the Korean peninsula.

After meeting with President Donald Trump on Thursday, Japanese Prime Minister Shinzo Abe said Japan and the whole international community was looking forward to the summit to open doors towards peace and stability for the region.

"If North Korea is willing to take steps towards the right direction, North Korea can see a bright future for itself," Prime Minister Abe said.

"Japan, based on the Japan-North Korea Pyongyang declaration, is prepared to settle the unfortunate past, to normalise our diplomatic relations and to provide economic cooperation."

For fishermen in Sakata, any diplomacy is unlikely to affect relations at sea for this season's fishing.

But they remain hopeful.

"I would like the illegal fishing to end," Captain Honma said.

"It's best if everyone can get along and fish while protecting the sea, not confronting North Korea.

"It's a matter of life or death for us when the fishing ground is being harmed. I hope we can get along and cooperate so the incidents like last year won't happen anymore."