BEIJING — It is a big vision on the drawing boards, a gleaming high-speed rail link between Beijing and Shanghai that could cut today's tortuous 13-hour trip to as little as 3 1/2 hours.
But as China considers a Japanese consortium's bid for the $12-billion train of the future, tensions from the two nations' wartime past have intervened, apparently stalling the bidding process and providing a stark illustration of how that lingering history can play a powerful role even as Asia's two biggest economies have become increasingly entwined.
Chinese officials gave strong indications this year that the famed Japanese "bullet train" technology would almost surely be used for the project, beating out other options that included German and French proposals.
But then signs of a surprisingly strong negative reaction emerged, including anti-Japan articles in some newspapers and a protest led by a nationalist group known as the Chinese Patriot Coalition, which garnered nearly 83,000 electronic signatures denouncing the use of any Japanese technology for the high-speed train.
The objections grew more bitter after metal scavengers at a dump in the northeastern Chinese city of Qiqihar last month unknowingly tore open buried containers of mustard gas that had been left by Japanese troops at the end of World War II. More than 40 people became seriously ill from the noxious substance, and one man died.
Despite Japanese apologies, medical help and discussions on compensation, the incident clearly aggravated the residual anger in China over Japan's brutal wartime occupation of the country. Indeed, in another Internet-based campaign, this one coordinated on seven Chinese Web sites, organizers say they gathered more than 1 million electronic signatures demanding Japanese compensation.
The chemical injuries seem to have aggravated old wounds to such a degree that they are having an impact, at least for the moment, on plans for the train of the future. As state officials and academics here describe it, it was no coincidence recently when China indicated it was likely to delay an announcement on the bid, and in fact was considering a plan to divide the project into components, raising the possibility that several countries might receive contracts.
For good measure, China's official New China News Agency reported that China might design and build the line itself, perhaps only "supplementing" the work with help from abroad.
The wording was ambiguous, and many experts here say China could eventually embrace the Japanese bid, perhaps after anger over the mustard gas casualties has abated. But for the moment, that anger has been acute enough to derail the bidding process, said Shi Yinhong, director of the Center for International Studies at People's University in Beijing.
"This is an economic issue that has been politicized," Shi said, "and not by the Chinese or Japanese governments, but by public opinion. China simply cannot make a very objective and rational calculation about the project right now."
Peter Hays Gries, a China expert at the University of Colorado at Boulder, said the fracas over the train is a vivid demonstration that "popular opinion and especially popular nationalism can be genuine constraints on policymakers in China."
Despite conceptions in the West that China's Communist Party leaders have a free hand to impose their decisions, the situation is more complicated, said Gries, author of a forthcoming book, "China's New Nationalism: Pride, Politics and Diplomacy."
"The timing of the mustard gas incident is probably very much on the minds of decision makers," Gries said. "It amounts to a very emotional issue, and they certainly do not want to hear charges that they are selling out the Chinese people. That is something that could be very dangerous to the party. And in that sense, they are very sensitive to domestic opinion."
The Chinese Patriot Coalition, which offers some of the most inflammatory anti-Japan statements, is run by a nationalist group whose Web site manager, Feng Jinhua, was jailed in Japan for a few months in 2001 for painting critical graffiti at a Japanese war memorial.
In a telephone interview, Feng said the train contract was "not a pure economic issue," because Japan still represented a potential strategic and even military threat to China.
"We are not against Japanese technologies," he said, "but we are against the idea that Japan might be able to control China via its technologies."
Among Chinese in general, there is tremendous respect for Japan's technology and economic advances, and many Chinese note an indisputable truth: that the two countries need each other. Japan has doubled its investments in China in the last five years or so, and by several measures the two countries amount to each other's most important trading partner these days.