Floating 2,000 pairs of socks over a heavily fortified border might sound like an eccentric form of humanitarian relief – but it could save lives, according to a North Korean defector I met yesterday at one of his regular balloon launches.

Lee Ju-sung came from North Korea to Seoul, via China, Myanmar and Thailand, in 2006, and soon after started using enormous helium balloons to send pamphlets over the border telling North Koreans about the better lives they could find outside their impoverished country. His own escape was partly inspired by a leaflet that he found in the woods, sent by the same means.

But last year he decided to start sending socks instead. These are a precious commodity in North Korea – particularly in the winter, when inadequate footwear can mean the loss of toes or feet to frostbite. Mr Lee often saw victims of this hobbling around on crutches, he said. And the relatively high quality of South Korean socks means they command a high price on the North Korean black market, where they can be exchanged for enough corn to feed a person for a month.

He’s now won the support of NGOs including a group of other defectors and people with relatives in the North, who are helping to fund his campaign. They were among about 50 people who turned out to assist yesterday’s launch at the Demilitarised Zone that divides the peninsula.

Mr Lee says interventions like his are the only way to get assistance to struggling North Koreans in the countryside: the millions of dollars’ worth of aid provided over the years by South Korea, the US and others has been almost entirely diverted by the Kim regime to reward party loyalists and help ensure its own survival, he argues.

I was struck by the seriousness with which he went about getting the balloons  and packages together – and by the thought that much of the humanitarian work done by North Korean defectors is motivated by feelings of guilt for the ones left behind. Families of defectors are often sent to brutal prison camps, sometimes for three entire generations, as Blaine Harden’s book Escape from Camp 14 explains. It’s a powerful means of discouraging thoughts of escape.

On the bus back from the DMZ, someone asked Mr Lee if any of his family members had been punished for his defection in 2006. He said that yes, bad things had happened to his extended family, and also to his friends. He didn’t elaborate. I was chilled to think of the anguish and sleepless nights those consequences of his escape must have caused him, as with so many other defectors, but he gave no outward sign of it at all.

I'm all for encouraging creativity in schools, but a responsible teacher would probably draw the line at telling the class to produce violent, xenophobic art aimed at a neighbouring country. 

That seems to be what's happened at one Korean school, judging by this Japanese website that I stumbled upon. It shows photos of a huge display of childish depictions of violence and hatred towards Japan. One shows three Koreans beating up a weeping Japanese person; others have the Japanese flag being burned, or given funeral rites, or about to be hit by a nuclear missile.

The reason for the recent outbreak of anti-Japanese sentiment in South Korea seems absurd to many foreigners: the countries' competing claims to two tiny, rocky islets, uninhabited save for a fisherman, his wife and a small South Korean police detachment. But for Koreans the symbolism of the Dokdo islands (Takeshima to the Japanese) is enormous.

Japan formally incorporated the islands in 1905, five years before it annexed Korea: the beginning of a 35-year occupation that involved terrible human rights violations, including the sexual enslavement of thousands of Korean "comfort women". Japan lost control of Korea when it was defeated in World War II, but it never relinquished its claim to Dokdo.

For Koreans, this seems needlessly stubborn, adding insult to the injuries suffered under Japanese occupation. A senior government official told me last month that Koreans are infuriated by Japan's perceived refusal to show proper remorse for what happened in those years - the comparison with Germany is often made.

So South Korean president Lee Myung-bak's visit to the islands last month set off a huge row between the countries, threatening hoped-for economic and military cooperation deals between them. Both governments seem to be taking ostentatiously tough stances on the subject to shore up support from nationalists at home. The Japanese government is under extra pressure given the simultaneous flare-up of a tussle with China over the Senkaku/Diaoyu islands.

The fight even overflowed into the Olympics - the South Korean footballer Park Jong-woo was denied a bronze medal after waving a placard inscribed with a Dokdo related slogan. (I noticed in Seoul's main square that people are collecting money to buy him a substitute one - see pic right.)

It's important for foreign observers to be sensitive to the problematic relationship between these two countries. Nonetheless, it is an enormous shame that relations seem to have taken such a turn for the worse at a time when the rise of China means it's in both nations' interest to forge closer ties. And they have far more in common - centuries of cultural osmosis have continued to the present day, with Japanese restaurants doing a booming trade in Seoul and Korean singers commanding huge followings in Tokyo.

Perhaps we should expect politicians on both sides to whip up nationalistic sentiments when it serves their purposes. But those children's drawings show the lasting, corrosive effects that can result.