HANOI -- The race has not yet officially begun, and the Japanese are already ahead.

While the Japanese government has pledged to honor the continuing U.S. trade embargo against Vietnam, Japanese companies have been quietly positioning themselves to move in en masse as soon as the embargo is lifted.

"The Japanese are playing it smart," said Eugene Matthews, an American business consultant now based in Hanoi. A fluent Japanese speaker, he advises U.S. and Japanese firms interested in investing in Vietnam. "They're training people now, helping to build up the human infrastructure that Vietnam lacks -- and getting themselves known. When the market opens up, they'll be right on top of it."

That's what many American companies are worried about. The American Chamber of Commerce in Bangkok has complained bitterly about lost opportunities for American businesses in Vietnam.

While the U.S. government holds firm on the 15-year-old trade embargo, a Japanese-Vietnamese trade association in Hanoi already boasts 70 member companies. Sanyo is about to open a representative office in Vietnam. Vietnamese workers in Ho Chi Minh City, formerly Saigon, are already assembling JVC stereo components through a joint venture with a Vietnamese firm. And Toyota, through a Thai affiliate, has prepared plans to set up passenger car assembling plants soon.

These ventures bend the spirit of the trade embargo -- without breaking it outright. The U.S.-imposed embargo blocks development aid and investment to Vietnam until a Cambodian peace plan is in place.

Because Vietnam occupied Cambodia for almost 11 years, ending in September 1989, the U.S. government still holds it accountable for Cambodia's continuing civil war. State Department officials have also linked the embargo to the still unresolved cases of Americans missing in action.

Assistant Secretary of State for East Asian and Pacific Affairs Richard Solomon recently told a conference of business people interested in investing in Vietnam that U.S.-Vietnamese relations may start to normalize within the next few months -- but not until these two issues are resolved.

Meanwhile, American business people visiting Vietnam to look for future investment opportunities are strapped by the Trading With the Enemy Act. Because of it, they can only spend $200 each per day -- an amount that could easily be eaten up by almost $9-per-minute calls to the United States. If they run out of cash, the act makes American charge cards worthless in Vietnam.

Japan's government may back the U.S. embargo in theory. But in practice it gives a wink and a nudge to Japanese companies eager to do their homework now on Vietnam, preparing to jump into the ready market of more than 60 million people as soon as the embargo is lifted.

"It's more important for Japan to keep good relations with the U.S. than to immediately break the U.S. boycott," said a senior Hanoi-based Japanese diplomat. "Japan is ready to start economic normalization and relations with Vietnam. But if the U.S. says the Cambodian problem is not solved, we cannot yet act."

But despite the official honoring of the U.S. embargo, some Japanese companies are shipping goods to Vietnam -- Hanoi's and Ho Chi Minh City's markets are already filled with cheap Sony televisions, Honda motorcycles and Toshiba appliances.

Like Americans before them, Vietnamese who can afford them seem to be becoming addicted to Japanese electronics. Imports from Japan to Vietnam soared from $91 million in the first eight months of 1989 to $169 million in the same period in 1990. Vietnam also boosted its exports of oil, frozen shrimp, scrap iron and timber to Japan from $219 million in January-August 1989 to $367 million in the same period this year.

Japanese traders admit the early stages of opening markets in Vietnam haven't been easy. They cite the combination of socialist lethargy and Confucian fear of angering one's superiors, with a confusing tangle of red tape thrown in for good measure.

Some private Japanese companies are also still waiting for the Vietnamese government to pay up on its $400 million in trading debts. An informed Japanese source in Hanoi said Nisho Iwai and Mitsubishi companies are owed the most, for goods supplied since 1983.

"The Vietnamese government ordered commodities without worrying about whether they had the money. It was in the five-year plan to get certain things, so they just ordered," the Japanese source said. "Now, they still have no money -- but they will probably try to pay back a small part of the total."

Some Japanese firms look to Vietnam's economically beleaguered socialist government, and say they won't invest in a big way until Vietnam is more politically stable. The Japanese government has a similar policy.

"The political situation now is quite negative for investment," said the Hanoi-based senior Japanese diplomat. "Japanese companies will only invest as long as it's profitable. As a government, our policy is if this country becomes more liberal, our support and aid will be greater."

Some Japanese business people who have already opened offices in Vietnam -- like their European and Australian counterparts -- accuse the government of price gouging. One example is that government ministries insist on supplying Japanese companies with all their locally hired staff -- at five times the usual salary. Most of the money goes to government ministries; the staff keeps very little.

Others gripe about Vietnam's crumbling infrastructure -- the tortuously pocked roads, the crackling and hissing telephone lines, the faulty electric supply.

But despite the complaints, new Japanese companies keep coming to Vietnam -- and old ones keep expanding. "It's been difficult to trade here so far, but that will probably change in the nearest future," said Koichi Kondo, representative in Hanoi for Japan's Shinwa Bussan Kasha trading company. "We must shake hands with each other, because we're all Asian people."