Americans who use kikkoman soy sauce probably think that, because of its name, it is imported from Japan. It is a typically Japanese product - but it is made in Wisconsin by a Tokyo-owned company that is so successful that it plans to export in addition to servicing the U.S.market.

The Kikoman plant is only one example of the increasing number of Japanese firms that sre setting up factories in the United States. Others include manufacturers of television sets, air conditioners and iron and steel, and there are even, in Kentucky, horse breeding farms run by Japanese.

Japan leads all other countries of the world in direct business investment in the United States. Total investment by the end of last year was estimated to be close to $4 billion, and it continues to climb.

Looking at this situation, industrial experts are raising the question of whether Japanese factories can function as effectively abroad as they do in Japan, where they can rely on a dedicated labor force and considerable government support.

Another question, posed by Yoshi Tsurumi in a recent study published under the auspices of the Harvard Business School, is whether the American and Japanese coporate cultures can operate together in enterprises established in the United States.

In Japan, for example, the emphasis is on teamwork, while U.S. managers are trained for specific responsibilities. American companies motivate employees by threatening them with dismissal in the event of failure. In Japanese firms, on the other had, executives take the blame for mistakes and workers must be guaranteed job security.

To a significant extent, however, both Americans and Japanese are going through a mutual learning process in the Japanese plants operated in the United States. Among other things, according to Tsurumi, the Japanese have come to appreciate American technicians, whose skills tend to be more wide-ranging than those of their counterparts in Japan. In contrast, the Japanese may have much to offer in the realm of labor relations.

One concern of Japanese automobile companies likt Toyota and Nissan as they contemplate the possibility of building U.S. factories is that they could face the kinds of labor disputes that are unknown in Japan, where strikes are a rarity. So far, though, the Japanese firms operating in the United States have found that the advantages outweight the risks.

An obvious advantage - and one that prompted Japanese companies to emigrate in the first place - is proximity to the American market.

Another advantage is the saving in transportation costs. The Kikkoman company, for instance, formerly imported American soybeans, processed them into sauce and sent the finished ingredient back to the United States. By locating its plant in Wisconsin, near the source of the raw materials, the company economizes on freight charges and is in a better distribution position.

Because the gap between American and Japanese wages is narrowing, it makes sense to manufacture in the U.S. Taking various Social Security charges into account, the difference betweenn labor costs at the Sony plants in Japan and in San Diego is almost negligible.

The protectionist atmosphere that lately has developed in the United States offers yet another incentive to Japanese firms to move across the Pacific. The limitations on exports recently negotiated by the U.S. and Japanese governments do not affect goods manufactured by Japanese companies in the United States.

For this reason, Sony has been joined by Matsushita, which recently purchased a subsidiary of Motorola, and Sony, which bought a controlling interest in Whirpool. The three companies, all of which bought a controlling interest in Whirpool. The three companies, all of which produce television sets, now can sidestep the voluntary restrictions that went into effect July 1 for three years.

The pioneer Co., another Japanese manufacturer of audio equipment, reportedly is planning to build an American factory. Honda, whose automobile sales in America are flourishing, is considering locating a motorcycle plant in California.

As the scope of Japanese investment in the United States increases, the potential for misunderstanding and perhaps even hostility may grow. But if Japanese firms continue to act as flexibly as they have until now, both they and American consumers can benefit in a climate of cooperation.