Datang produces an astounding nine billion pairs of socks each year -- more than one set for every person on the planet. People here fondly call it Socks City. Southeast from here is Shenzhou, which is the world's necktie capital. To the west is Sweater City and Kid's Clothing City. To the south, in the low-rent district, is Underwear City. This remarkable specialization, one city for each drawer in your bureau, reflects the economies of scale and intense concentration that have helped turn China into a garment behemoth. The niche cities reflect China's ability to form "lump" economies, where clusters or networks of businesses feed off each other, building technologies and enjoying the benefits of concentrated support centers -- like the button capital nearby, which furnishes most of the buttons on the world's shirts, pants and jackets. Just wait until they focus on software. You'll have AntiVirus Village, Middleware Mountain, Browserborough, and more. (Microsoft Research already has a major presence in China.) Or, even more specialized ... a city for device drivers, one for user interfaces, another for kernel hackers, and still another for databases. In the next few years, once all the limits are lifted, China's share of the US apparel market could soar to 50 percent to 70 percent. With those numbers, you can't blame it all on Wal-Mart. Sweaters Are West of Socks City | 
