NEW YORK (AP) _ While the Japanese have irked President Clinton and American exporters because of a relentlessly growing trade surplus, some savvy U.S. investors have been savoring Japan as the land of the rising stocks.

The Tokyostock market, which has languished because of a deep recession in Japan, has been arousing widespread attention with a powerful rally lately. The Nikkei average, the most widely followed barometer, closed above the 20,000 level this past week for the first time in more than a year.

The most recent catalyst was an economic stimulation package worth about $115 billion unveiled by the Japanese government. That's more than six times what Clinton has proposed for pumping the American economy and more than triple what the rich industralized nations have proposed for aiding Russia.

It would finance Japanese public works projects ranging from highways to housing, fiber optic networks to personal computers for schools.

''Obviously we're talking about a fair amount of money,'' said Jon Choy, senior economic analyst at the Japan Economics Institute of America, a Washington-based organization financed partly by the Japanese government.

Tokyo officials say some of that money will find its way into American hands and help shrink the trade imbalance, as U.S. businesses win building contracts and orders for goods and services in Japan.

To what extent that happens remains unclear. But for Wall Street professionals who view opportunities through borderless binoculars, Japan's effort to spend its way out of an economic malaise is good news regardless whether it helps reduce U.S.-Japanese trade tensions.

Merrill Lynch & Co. strategists, for example, have been strongly endorsing purchases of Japanese stocks for some time, partly on the hunch that such aggressive steps by Tokyo would be inevitable.

In their view, the earnings of Japanese corporations could rise in the their next fiscal year by 35 percent or even more if a recovery in Japan takes hold.

''The Tokyo stock market's been in a bull run in anticipation of this,'' said William Sterling, an international economist at Merrill Lynch.

As for investors in this country who are just waking up to what's happening in the Japanese market, Sterling said, ''they clearly missed the bottom. A lot of people out there will be playing catchup.''

Years ago, ordinary Americans looking for places to make their money grow might have shrugged off this news. But the globalization of the investment world has made it relatively easy for them to put their money to work in Japan, or nearly anywhere else, by placing an order with their local broker.

The stocks of many leading Japanese corporations, for instance, are traded in this country, in dollar-denominated units known as American depositary receipts or ADRs. They behave like their native kin in Japan.

A look at a few of these ADRs shows just how far they've come. The camera- photocopier maker Canon, for example, has risen 25 percent since the beginning of the year to $68 per share; Sony has risen nearly 28 percent to $44 pere share; Toyota has risen 32 percent to the $31 level.

In addition, a number of U.S.-based mutual funds specialize in Asian securities, doing the research homework and possessing the wherewithal to purchase a range of Japanese stocks traded only in Japan. These funds have drawn increasing interest as the Japanese stock market has strengthened.

Morningstar Inc., a mutual fund reporting service in Chicago, said in a recent newsletter that bargain-hunting investors have been pouring money into such funds as G.T. Japan Growth, Japan Fund, DFA Japanese Small Company, and Vanguard International Pacific Index.

The net asset values in this category of funds, equivalent to the prices per share, have been surging lately to their highest levels in the past year. GT Japan Growth, for example, hit a 52-week high of $10.66 level this past week; the Fidelity Pacific Basin Fund, which has been increasing its exposure to Japanese stocks, hit a 52-week high of $14.22.

''The Japanese stimulation package is going to give the economy there a good boost,'' said Bob Evans, international portfolio manager for Pacific Investment Management Co., a Newport Beach, Calif., money management concern. ''It's clearly positive for equities.''

Nonetheless, there is considerable skepticism about the true strength of the Japanese stock market. Some experts familiar with the Japanese economy already see the market's big jump as a disturbing similarity to the speculative frenzy that inflated asset values there in the 1980s.

''It seems to me we're back to the bubble again,'' said Robert Z. Aliber, an international economist at the University of Chicago, who specializes in Japan.

Morningstar mutual fund analyst Tom Desmond also warned of the investment risk that Japan's market presents. Buyers of Japanese-focused mutual funds, he wrote, ''should expect a potentially volatile ride.''

End Adv for weekend editions April 17-18