A passenger ferry that ploughs the 1,000 kilometres between western Japan and North Korea has become the unlikely focus of Japanese fear and suspicion of its unruly neighbour.
By Sarah Buckley
BBC News Online
The Mangyongbong-92 may not look like a smuggling or spy ship - its main occupants are elderly ethnic Koreans paying visits home, and students taking their annual school trip to the "homeland".
The Mangyongbong carries Japan's ethnic Koreans to the North
But the ferry has become the centre of rumours of North Korean subterfuge, and the focus of general animosity fuelled by Pyongyang's admission last year to abducting Japanese citizens in the 1970s.
The current mood could jeopardise the sole passenger link between Japan's Korean community and their relatives in the North.
On Monday, North Korea prevented the Mangyongbong from making a scheduled docking in Niigata, Japan, after Japanese authorities threatened to comb it for suspect cargo.
The Mangyongbong was built in 1992 with funds from Chongryon, or Chosen Soren - the pro-Pyongyang General Association of Korean Residents in Japan.
The 350-capacity ferry makes about 20-30 trips a year between Niigata and North Korea's Wonsan.
On one trip to North Korea in November, the Japanese Sankei Shimbun newspaper reported that it was carrying a special delivery of tropical fruit for the country's leadership.
But according to the Mangyongbong's detractors, Korean passengers and presents are not the ship's only cargo.
A North Korean defector told a US Senate committee hearing last month that the ship carried 90% of the rogue state's missile parts.
His allegations followed a report by Japanese intelligence in January that the captain of the Mangyongbong had relayed espionage orders from North Korea to a 72-year-old former official of Chongryon.
The head of Chongryon's foreign affairs bureau, So Chung-on, denied this, and other reports that the ship was used to smuggle large amounts of cash to the North.
"I think the recent rumour about the Mangyongbong is fired up by the American CIA. They try to control North Korea politically and economically," he told BBC News Online.
Haturu Nomura, the author of Suspicion About Money Transfers to North Korea, agreed that the amount of money taken by the Mangyongbong, which peaked at around 20bn yen ($170m), was now "negligible" because of the dire state of the Japanese economy.
He said that the real source of contraband to North Korea were ships that travelled via a third country - to China, Russia, or South East Asia.
Alexis Dudden, a US historian specialising in the region, said she "would suspect (the Mangyongbong) has been the source of large engineering parts (but) I would imagine the truly illegal stuff goes on in a much more clandestine way".
Nevertheless, members of the Japanese Government have called for the Mangyongbong to be banned from docking in Japan, and the Prime Minister Junichiro Koizumi has called on the police agency and Customs officials to step up their checks of the ship.
Ichita Yamamoto, deputy director of the ruling party's committee on foreign affairs, said that although there are limits to what the ship can carry, it had not been checked at all until a few months ago, partly because "it's quite a sensitive issue for Japan".
Many of the 600,000-strong ethnic Korean population are only in Japan because they were forcibly brought to the country as slave labour during World War II.
Alexis Dudden said that despite the current attention on the Mangyongbong, the searchlight on illegal activity between Japan and North Korea should actually be trained on pachinko, a pinball-type gambling game.
According to the Federation of American Scientists (FAS), nearly one-third of the pachinko industry is controlled by Chosen affiliates or supporters.
"That's where the real story is in the long run," Ms Dudden said, saying that there were widespread suspicions that there were close connections between the pachinko industry, the yakuza - Japan's mafia - and levels of the Japanese Government.
But she said that the sensitivity of the subject obstructed substantive analysis.
"I have barely scratched the surface and I've received three death threats," Ms Dudden said.
Meanwhile the most high-profile link between Japan and the North is under threat. Even, if legislation and public opposition do not ground the Mangyongbong, sheer lack of means might.
According to Japan's Kyodo news agency, a Tokyo company that regularly supplied oil to the ship has said it would no longer do so, following the accusations that it is carrying out illegal activities.