TOKYO, JAN. 28 -- California-based Intel Corp. has sold an early model of its new parallel-processing supercomputer to an arm of the Mitsubishi group, scoring a major American coup in a key high-tech field that the Japanese government has targeted for world domination.

By successfully marketing its iPSC/860 supercomputer to Mitsubishi Precision Co., the American maker beat out Japanese supercomputer firms on their home turf, even though Japan's Ministry of International Trade and Industry (MITI) has mounted a major effort to make Japan preeminent in such high-speed, high-capacity computer equipment.

"Of course we feel great to have cracked the supercomputer market here," said William Howe, president of Intel's Japan arm, "and particularly with a parallel-processing computer, when MITI is really promoting that architecture as an area for Japan."

Intel's successful introduction of its new supercomputer here runs counter to the gloomy views of analysts who had predicted that the combined efforts of Japan's government and its formidable computer industry would make this country master of the world market in parallel-processing supercomputers.

Actually, Japan is still trailing the United States by a considerable distance in supercomputer technology and sales. The Japanese makers -- notably NEC Corp. and Fujitsu Ltd. -- have sold only three to five supercomputers between them in the United States, by some estimates.

Meanwhile, Minneapolis-based Cray Research Inc., the world leader in supercomputers, has sold about 20 of its computers here. Cray is likely to pass Fujitsu this year to become the leading seller of supercomputers in Japan. And now Intel is getting into the act.

The term "supercomputer" refers to a species of machine that can handle huge numbers in mathematical calculations at high speed. The U.S. Trade Representative's office defines a supercomputer as any calculating device that can carry out more than 300 million mathematical operations per second.

Intel courted Mitsubishi Precision, a maker of simulation machines for pilot and driver training, for about eight months before landing the sale last month, Intel officials said. The sale has not yet been formally announced in Japan, evidently because Mitsubishi didn't want to make the purchase public. The price of the new computer was not disclosed, but similar Intel machines have sold for around $1 million each.

Intel's success in Japan has an ironic twist. The American firm, founded in 1968, was the first company to sell computer memory microchips. But Intel and other American chipmakers eventually quit the memory business because of the heat of Japanese competition.

After that setback, Intel came to rely more on manufacturing of microprocessor chips -- that is, the central switchboard and calculating chip at the heart of modern digital computers. Intel has achieved considerable success in Japan selling microprocessors, a type of chip that offers a much higher profit margin than the cheaper memory chips.

Intel is a relative newcomer to the world competition in supercomputers, the biggest and fastest scientific and industrial computers. Its distinctive competitive edge has come from its use of "parallel-processing" design, in which dozens or hundreds of processor chips work simultaneously -- in parallel, as the computer experts put it -- to solve a problem.

This same parallel-processing approach is the heart of MITI's newest program to make Japan the world leader in supercomputers.

According to a recent report from the White House Office of Science and Technology Policy, MITI's "6th Generation Computer Project" -- the agency's effort to steer Japanese computer makers in profitable new directions -- will also focus on parallel processing.

The U.S. government also has played an important role in computer development. Intel's computer is partly the product of a development effort called the Touchstone program, overseen by the Pentagon's Defense Advanced Research Projects Agency, known as DARPA.