Doraemon has just celebrated a rather strange centennial. The time-traveling robot cat has become internationally beloved since making his debut in a 1969 Japanese comic, to the point that Japan’s Foreign Ministry recently made him a cultural ambassador. This year represents a sort of pre-anniversary — canon has it that he was created in the year 2112, so enterprising 7-Eleven stores across China have been selling all manner of Doraemon-related merchandise.

Which was all very well, until it suddenly became rather bad news to be a Japanese icon in the Middle Kingdom.

This past Tuesday, September 18, was the anniversary of the 1931 Manchurian Incident, widely acknowledged to be a pretext for the Japanese to invade northern China and begin an occupation that would last 14 years. The Chinese government regards the day as a reminder of a “national humiliation”; Chinese citizens speaking to Crikey say that in years past it has been a day of solemn mourning.

This year was different. Protests simmered at the Japanese embassy, and many Japanese businesses and commercial outlets gave staff holidays and closed their doors as a precaution. Some shops covered their logos and signage in heavy red banners that brandished patriotic, pro-Chinese slogans like talismans to ward off evil. 7-Eleven, a subsidiary of Japanese department-store giant Seven & I Holdings, was no exception; 198 of the convenience stores were closed across China.

This thunderhead began to brew in April, when Tokyo’s right-wing governor Shintaro Ishihara announced plans to buy a cluster of eight uninhabited islands in the East China Sea from their private owners. These islands, called Diaoyu in China and Senkaku in Japan, are thought to harbour mineral resources and have long been the point of low-key squabbling between Japan and China, and to a lesser extent Taiwan.

China says it has maintained a naval defence of the islands as far back as the Ming dynasty (1368-1644), but their modern history begins when they were annexed by the Japanese at the end of the Sino-Japanese War in 1895. More than a century of tit-for-tat manoeuvres has followed — China points to two declarations in World War II that gave it control once more, but the Japanese argue that a 1951 treaty gave them to the US, which meant the US’ decision to return them to Japan in 1972 was above water.

In the months since April, both countries have landed on the islands to plant flags, inflate chests and spout rhetoric. July saw Japanese Prime Minister Yoshihiko Noda declare that negotiations for a transaction were under way. All the while, Japan was collecting money from the public and its reserves, and a week ago, on September 11, Tokyo announced it had struck a 2.05 billion yen ($26.26 million) deal to purchase three of the islands.

China was most displeased. Among the milder responses was the official word from its Foreign Ministry, which released a report using language that would give Basil Fawlty kittens: “Japan’s stance on the islands is a blatant denial of the victory of a global anti-fascist war and a serious challenge to the postwar international order.”

To borrow a dexterous description from The New York Times, the protests that followed have been “at least tolerated” by the Chinese government. There have been stories of verbal and occasional physical violence towards Japanese nationals in China. Vandalism has been reported, with Japanese cars a favoured target, and fully decked-out riot police and their plainclothes counterparts have carefully chaperoned protests in some cities.

At the Japanese embassy in Beijing, projectiles have thus far been limited to fruit, eggs, plastic bottles and creative epithets. The crowd at the heavily guarded compound seemed strangely organised at times, as if the protesters were taking shifts to ensure a healthy number remained at the gates.

China’s Communist Party has been a little less organised of late, but the furore over the islands has helped it pull off a delicate balancing act — anti-Japanese sentiment has kept the party visible during the mysterious two-week disappearance of Xi Jinping, China’s leader-in-waiting, who missed several meetings with foreign dignitaries during his absence.

Xi popped up again this past weekend to meet visiting US secretary of defence Leon Panetta, who did remarkably little to quell international worries about war between the bickering countries. Panetta did, however, find the time to announce that the US had agreed to put a second missile defence system in Japan.

Other developments continue to unearth memories of times when Sino-Japanese relations were tragically ballistic. Victims of Japan’s Chongqing bombing campaign during World War II filed a lawsuit against the Japanese government this month, while those affected by mustard gas left over from the Japanese occupation are back in a Tokyo court to seek compensation. But the most interesting aspect of the dispute over the islands has been the reaction among China’s 20- and 30-somethings.

A patriot? Doraemon caught between Japan and China

A China Daily report points out the conflicted emotions of China’s youth, many of whom grew up steeped in Japanese culture at a time when China had reopened its doors to the world. There is a reason Doraemon is popular in this market — so are other Japanese manga and anime, along with the country’s music and movies. But the protests have galvanised this subsection of the populace, many of whom are eager to share their decisions to boycott Japanese products and take advantage of their employers’ decisions to give them time off to attend protests.

“He is a patriot,” said one such employee of his boss. “We just can’t endure it any longer. It’s like a robber breaking into your house and trying to steal your belongings.”

If many Chinese have their way, few of those belongings will have their origins in Japan. Nissan has blamed increasing anti-Japanese attitudes for its poor performance in the Chinese car market this year, while Toyota and Mitsubishi have seen drops in their market share. Hundreds of flights to Japan during China’s week-long National Day holidays in October have been cancelled, and some Chinese experts believe this sentiment could spread to other sectors such as mobile phones and computers.

Incredibly, there is yet another important date in Sino-Japanese relations looming — September 29 will mark 40 years since the establishment of diplomatic relations between Japan and China. Yesterday, some of the slogans and banners adorning Japanese-affiliated shops had been removed, but this hardly represents a return to that sort of cordiality — most 7-Elevens still had their logos sheathed in black plastic, and discarded in a dustbin outside one franchise in Beijing’s Chaoyang district were boxes cheerfully emblazoned with pictures of Doraemon.

It hasn’t been a good month for anniversaries.