ABOUT three thousand protesters gathered outside Shanghai’s Japanese consulate on September 16th. The young crowd, mostly aged 20-35, had draped themselves with the Chinese flag, chanting anti-Japan slogans and brandishing portraits of Chairman Mao. But the presence of riot police and soldiers had a sobering effect. Even as the protesters shouted for Japanese nationals to “get the hell out of China”, they waited obediently before filing towards the gates of the consulate in batches. Each group had an allotted ten-minute remonstrance at Japan’s official doorstep. They took their banners with them when they made their orderly series of exits. Elsewhere things have been less peaceable. Over the weekend anti-Japan-themed protests erupted in dozens of Chinese cities, in what one observer has called the largest such widespread display since Japan established diplomatic relations with the People’s Republic in 1972. In Shenzhen, which borders Hong Kong, police used tear gas to control crowds. In Guangzhou 10,000 protesters took to the streets, according to the Japanese press. A Panasonic factory and a Toyota car dealership were both set on fire in the port city of Qingdao, as were Japanese-made cars in Xi’an. The embassy in Beijing got off lightly by that measure, being pelted with eggs and rocks. Anti-Japanese tension, never far below the surface of public life in China, has bubbled to a boil over the past few weeks. On September 11th the Japanese government outraged China by buying the three Senkaku islands from a private owner, the only three it did not already possess. The islands as a group are known as the Diaoyus in China, which claims them as its own. On September 14th, Japan’s coast guard reported that six Chinese patrol ships entered Japanese territorial waters, in an apparent provocation. They left a few hours later. The Senkakus—a straggle of rocky islets 200 nautical miles (370km) from China—have been a site of contention for decades. But the Sino-Japanese fissure runs much deeper still. Bitterness over Japan’s imperial aggressions in the 1930s and ’40s is tangible today. September 18th will mark the anniversary of the 1931 Mukden Incident, when Japanese forces took Manchuria and embarked on their 14 years of pillage and suppression. The weekend’s protests may yet intensify, though they will remain under watch. Mass protests do not occur in China without some degree of official forbearance.

Japan’s prime minister, Yoshihiko Noda, has urged the Chinese government to protect Japan’s citizens resident in China. (Diplomatic relations were further complicated by the inauspicious news of September 16th: the new ambassador to China, Shinichi Nishimiya, died suddenly in Tokyo.)

Mr Noda’s plea followed a spate of minor physical attacks on Japanese nationals in Shanghai, which is home to 60,000 Japanese expats. In one incident, noodles were thrown in the face of a Japanese man. Another had his glasses smashed. Mr Noda is keen to avoid the sort of demonstration seen in the city in 2005, when tens of thousands of protesters took to the streets, physically assaulting Japanese nationals and smashing the windows of Japanese-owned businesses.

At the Shanghai protest, a Mr Tong, 35 years old and wearing a T-shirt that says “overthrow the Japs, defend Diaoyu”, had just finished a bout of demonstrating. Mr Tong says losing the islands would be a national humiliation. “China has the power to say ‘no’ to Japan and the government should play the hard line.” Citizens, he says, should boycott products made in Japan and stop travelling there. A handout listing the Japanese brands that are to be shunned was circulating among the protesting crowd.

Mr Tong does not support the violence that is cropping up in other cities. It would be misdirected, anyway. According to Mr Tong there is more to such outpourings than the old anti-Japan feeling. People’s frustrations at other social injustices, he says, have been suppressed for too long, becoming mixed up in this issue. The test for authorities will be dissolving public anger while maintaining the peace. In Shanghai, for now, things seem under control.

(Picture credit: The Economist)