Before 1999 London had just one regular contemporary art fair, remembers WillRamsay, boss of the expanding Affordable Art Fair. This year around 20 will be held inBritain, mostly in the capital. Roughly 90 will take place worldwide. The success of largerevents such as Frieze, which started in London, has stimulated the growth of smallerfairs specialising in craft work, ceramics and other things. Artl4, which started last year,specialises in less well-known international galleries, showing art from Sub-SaharanAfrica, South Korea and Hong Kong.
    One explanation for the boom is the overall growth of the modern-art market. Four-fifths of all art sold at auction worldwide last year was from the 20th or 21st century,according to Artprice, a database. As older art becomes harder to buy--much of it islocked up in museums--demand for recent works is rising.
    London's art market in particular has been boosted by an influx ( 流 入 ) of richimmigrants from Russia, China and the Middle East. "When I started 23 years ago Ihad not a single non- Western foreign buyer," says Kenny Schachter, an art dealer. "It'sa different world now." And London's new rich buy art differently. They often spendlittle time in the capital and do not know it well. Traipsing ( 游 艇) around individualgalleries is inconvenient. The mall-like set-up of a fair is much more suitable.
    Commercial galleries used to rely on regular visits from rich Britons seeking tofurnish their stately ( 富 丽堂皇的 ) homes. The new art buyers have no such loyalty.
    People now visit galleries mainly to go to events and to be seen, says Alan Cristea, agallery owner on Cork Street in Mayfair.
    Some galleries are feeling squeezed. Bernard Jaeobson runs a gallery opposite Mr.Cristea. The changing art market reminds him of when his father, a chemist, was eclipsedby Boots, a pharmaceutical chain, in the 1960s. Seven galleries in Cork Street relocatedthis month to make way for a redevelopment; five more may follow later this year.
    Yet the rise of the fairs means galleries no longer require prime real estate, thinksSarah Monk of the London Art Fair. With an international clientele, many can work onlineor from home. Although some art fairs still require their exhibitors to have a gallery space,increasingly these are small places outside central London or beyond the city altogether.
One gallery owner says few rich customers ever visit his shop in south London. He makesall his contacts at the booths he sets up at fairs, which might be twice the size of his store.
    "It's a little like fishing," he explains. "You move to where the pike is."