BACHENG, CHINA — Crab is prized in China year round — it's a dish with "special moment" written all over it in the Chinese family. But in November, when the hairy crabs of the Yangtze delta start developing egg roe, a special passion takes hold. And this fall, it has reached new depths.

The object of recent Chinese desire is a feisty fist-size freshwater bottom-dweller harvested from a single lake near Suzhou. Known as the Yangcheng Lake hairy crab, it enjoys a unique habitat: iron-rich soil that leaves a yellowish tint on the claws, a hardpan lake bottom that forces the crab to develop muscular legs and shallow sun-filled waters that supposedly promote robustness. The combo makes Yangcheng the Rolls Royce and the Vidalia onion of China's crab world.

For years, Yangcheng crabs were mostly found in kitchen steamers in Shanghai and Hong Kong. But now, the crab's rise in power and popularity has begun to parallel China's own: In an urban China of status and money, Yangcheng crabs have achieved, very quickly, a reputation as the finest and purest flavor in the crab palate.

What's more, for an expanding middle class with disposable income, leisure time and a relatively new love of eating out, the lake crab is an attainable if expensive delicacy. It has a dark green compact shell, hair on its legs and around its underbelly — and nearly all are imported from the Yangtze River as babies the size of quarters.

Markets for authentic hairy crabs, combined with even larger markets of fake hairy crabs, run in the hundreds of millions. Prices for authentic Yangcheng crabs have bubbled up to as much as $45 per crab, from $5 a crab in the 1990s.

"Crabs come in a thousand flavors in China," says Ping Yuan, an executive chef in Beijing. "But the Yangcheng lake crab is No. 1. The flavor is amazing, and the whole country wants to eat it. But most of what is available are Yangcheng fakes."

Food in modern China is of enormous cultural importance. Seafood is at the top of the hierarchy — something with status to share with friends or on special occasions.

Technically, crab exists in the middle of the seafood hierarchy. It doesn't carry the same status heft as lobster, shark fin or abalone. But for ordinary Chinese, the crab is special. In the popular imagination of an aspiring middle class, crab reflects prosperity in a way that elite dishes like shark fin probably never will.

Few families would countenance a crab dinner, for example, without the father or mother present. Nor is the delight in the experience of wolfing down chunks of meat, as per the lobster; in fact, a hairy crab has precious little meat. Lake crab is all about savoring the flavor.