SHANGHAI — A few years ago, China's state-run news agency published a tiny article about a remarkable change: "All 108 outdoor farmers markets in downtown Shanghai have been moved into various halls and houses."

Markets, it explained, "have badly affected the surroundings and the traffic." Another 100 street markets, it added, "will also be demolished." The news didn't earn more than four crisp paragraphs, but it captured the essence of China's national transformation: It's abrupt, it's vast, and it might include demolishing your neighborhood.

That specter of change looms over Shanghai's Da Jing street market, the throbbing central artery that feeds this city's most ancient neighborhood — the kind of place where pig trotters arrive still warm from slaughter and drying squid dangle over the street like wind chimes. So far, this neighborhood, parts of which are 700 years old, has been spared by progress. It probably won't be for long.

"China has changed, but life here is the same as it was 50 years ago," said Shanghai-born chef Steven Miao, scanning a mountain of fresh green fava-bean shoots just after dawn one weekday morning.

In a city that worships the new and the sleek, the street market at Da Jing Road is willfully out of step. It is a splendid jumble of centuries, full of sizzling pot stickers and bleating cell phones, pungent rice wine and bullfrogs as plump as softballs.

To some in China, this market, and others like it from Beijing in the North to Kashgar in the West are just holdovers from China's bitter past, the many centuries of airless apartments and simple meals. Many in China's rising middle class prefer the immaculate aisles of Wal-Mart and Carrefour, and it's impossible to begrudge them that.

The Da Jing street market is little more than a few narrow intersections, barely six blocks long. But for a visitor, it is a living, breathing education in Shanghai cuisine, a style distinguished by its thick savory sauces spiked with sugar and soy sauce.

But this neighborhood is not the Shanghai that China puts on postcards. That is the Pudong district on the east side of the Huangpu River, where a forest of shimmering office towers has sprouted in barely a decade, testifying to Shanghai's revival. Nor is this the musty old-world district on the river's west bank, the Bund, where generations of foreign traders and adventurers laid their first roots in China.

Rather, this is Shanghai's guts, nestled south of the Bund, where streets narrow into a warren of alleys and tenements that are filled with the sights and smells of food.

Like most markets, Da Jing is most alive just after dawn, when the elementary-school children in their uniforms and bright red kerchiefs set off through narrow streets, marking the start of another frenzied day of commerce.

You won't get far before encountering a fishmonger, standing over plastic tubs sloshing with fresh catch. Although Shanghai is on the sea, it long lacked the prosperity that Hong Kong enjoyed, so while Hong Kong became known for its exotic ocean creatures, Shanghai built its diet around more commonplace river and sea fish. And it puts them to creative use: Even a cheap trout, deep-fried and sprinkled in cinnamon, will make an interesting appetizer with a smoky flavor.

Strolling through the market, Miao, now a chef at the Four Seasons Hotel, stopped at a breakfast stall preparing deliciously golden brown youtiao, a Chinese cruller that is salty rather than sweet.

"In my childhood, this was a luxury," Miao recalled. "We had it once a month. It was rich people's food. Usually, we only had congee."

RICH VS. POOR

Anywhere in China, food is a barometer for affluence. And here, the city's characteristic sauces emerged because meat was a luxury usually out of reach.

"Shanghai food was for laborers," said Jiang Liyang, an author of four books on the city's food. "They didn't have enough fat to put in their stomachs so they used a lot of oil. And they used soy sauce instead of salt because salt is hard to see and nobody could guarantee that you put salt in the dishes."

Not far from the youtiao dealer, another fish vendor showcased boxes of glistening freshwater crabs. Shanghai diners save crabs for special occasions, like a homecoming, when they can linger over the table for hours. Other kinds of crab can end up in xiaolongbao, or little steam-basket buns, a divine dumpling that carries a teaspoon of soup inside each doughy bundle. The best ones in Shanghai have a skin delicate enough to see through.

Of course, no market in Shanghai could be complete without a rice vendor. Southern Chinese like to emphasize that their northern brethren have no knowledge of rice, subsisting instead on steamed bread and noodles. But here a vendor will often stock at least six varieties of white rice, with grand titles such as "Northeast Long Fragrant" and "Pearl River Fresh."

In China, where the word for rice is a synonym for food, all major varieties will someday end up in Shanghai. Likewise, the market itself is the destination for migrants and strivers from across the Chinese countryside, some of the hundreds of millions of farmers who have trekked to coastal cities this decade in the largest peaceful migration in world history.

Yu Defang, 41, moved to the market from a village in far southern Jiangxi province 14 years ago. Now, every night at midnight, her husband wakes up and takes a bus to the city's edge to buy and slaughter the meat for their butcher's stall. Typically, two or three small butchers will divide one pig a night. Life is stable, Yu said, though rumors of demolition leave vendors like her on edge.

"Business is tough now because people in the neighborhood are starting to move out," said Yu, hunks of pink pork suspended on hooks overhead. "But a supermarket can never be as good as this place. A supermarket is too expensive, and you can't get to it from the neighborhoods."

For the people who depend on Da Jing, it is a kind of proto-mall. Mrs. Zhou, a formidable woman in her 50s, clad in elbow-length purple gloves, had several errands to squeeze into her lunch break. She had already picked up a hunk of ginger and a fat bundle of scallions for dinner, and their dewy green shoots bristled through the wire of her bicycle basket. Before leaving, she had stopped to buy a bing, a small, pillowy flat bread.

But the vendor was trying a classic bait-and-switch, stuffing the bag with cold, hour-old bread instead of the piping-fresh loaf that was steaming the glass of the display case. Mrs. Zhou barked at the young woman in the paper hat and pointed vigorously at the freshest loaf. Mrs. Zhou, of course, prevailed.

"You have to pay attention here," she said, noting that shopping in a Chinese market is not, in the usual sense, relaxing. "But I always come because it's cheap and it's the best."

UNCERTAIN FUTURE

The talk of demolition is constant and unspecific. Nobody seems to know any details, except that it is almost sure to be complete before 2010, when Shanghai is scheduled to host business leaders for the World Expo. For 72-year-old Fan Liya, that would mean leaving the home where she has lived since childhood, a home that has seen five generations of her family. Asked about moving, she offered a weak smile.

"We can't forget our history," she said.