(FORTUNE Magazine) – AN EXTRAORDINARY arena of growth in a listless global economy. A battleground for the competition between the U.S. and Japan. This is booming, ambitious East Asia. America and Japan have slowed down, partly as a result of the various middle-age maladies of mature industrial states. In addition, Japan is going through wrenching political and social change (see following story). But both economic superpowers still find plenty of customers and low-cost producers in Asia. The rising powers in the region are developing countries -- from Thailand and Malaysia to China. Much of their manufacturing prowess comes from Japanese and American investment and expertise. Singapore makes about half of all computer hard-disk drives because Seagate, Western Digital, and other U.S. producers have factories there. Likewise, a Sony factory enables Singapore to provide some 30% of the pickup devices for compact-disk players. China's exceptional growth, 14% in the first half, was faster than its evolving political and economic institutions could digest, which could slow $ -- though not halt -- its drive toward a market economy (see ''China: Struggle for Control''). The economies of the newly industrializing Asians will expand an average of 8.7% this year, vs. world growth of just 2.2%, according to the International Monetary Fund. These nations are getting richer probably faster than any in history. Asia just three decades ago accounted for only 4% of the global economy but now provides one-quarter of it -- and by the year 2000 is likely to contribute one-third of all economic activity on earth. Working hard, saving ardently, and exporting vigorously have made many Asians wealthy enough to become champion consumers. Taiwanese paid $100 or more for tickets to a Michael Jackson concert last summer. The big spenders in the shopping centers of Hong Kong and Singapore are not Japanese, Europeans, or Americans but Indonesians buying diamond-studded watches, farmers from Taiwan acquiring trinkets from Tiffany's, and mainland Chinese neocapitalists hungry for just about everything. In Kuala Lumpur, Malaysia's capital, smartly dressed businesswomen stroll the streets while talking on cellular phones. Bangkok's roads are jammed with Japanese cars. Increasingly, U.S. and Japanese companies contend for the genuinely big-ticket sales, such as power plants and telecommunications networks. Says Stephen G. Butler of the accounting and consulting firm KPMG Peat Marwick: ''The need for power projects alone will total $1 trillion over the next 20 years.'' No wonder America is trying to get closer to the action. As Winston Lord, Assistant Secretary of State, says, ''Today no region in the world is more important.''