During the Korean war in the early 1950s, Japan's industries were so weak and the quality of their output so unreliable that the U. S. government sent aid money and technical missions to shore them up.

Now American industry is suffering from stagnant productivity, erratic quality and outmoded technology while Japan is thriving, and U. S. business is seeking help from the Japanese.

Beginning in February, the U. S. Chamber of Commerce will be taking American industrialists and executives on intensive tours of Japan to study Japanese business methods and factory operations and to search for ideas that could be applied to their own firms.

The two-week tours will amount to crash courses in how the Japanese run their factories, conduct their labor relations, develop their markets and finance their capital expansion. "This is not a junket," said Carl Noller, director of the chamber's Productivity Center. "This is for people who are seriously interested in what's going on in Japan."

The Americans will visit Japanese trade unions, factories, shipyards--including such giants as Nippon Steel and IHI Shipbuilding--and will examine Japanese training and marketing methods to see why, as Noller said, "Japanese productivity has increased five times faster than ours for 30 years."

In Japan, the tours are being set up in cooperation with the Japan Productivity Center, an organization created by Japanese industry to compile information on technological and managerial developments. Ironically, the center was established with U. S. government assistance in 1955. Now it has a Washington office to give back some of the help.

Joji Arai, the center's Washington representative, said the Japanese recognize that "strengthening the industrial base of the U. S. is vital for the survival of Japan" and it is in Japan's long-term self-interest to share its industrial know-how with the United States.

Noller said he is "constantly amazed" at how little U. S. business executives and plant managers know about their own shortcomings and about Japanese industrial advances. He and Arai share the view that the boom years after World War II lulled American industry into complacency because the United States had an enormous technological lead over other nations and domestic markets were growing rapidly.

Now the rest of the world is catching up, and in some areas the Japanese have moved ahead. "They don't have all the answers, but they have done phenomenal things in some areas," he said.

Noller cited four areas where Americans could learn from Japan: human resource management, "process skills" and technology, quality control, and strategic and financial planning. Each of the four two-week tours for 20 participants that the Chamber of Commerce is organizing will concentrate on one of those subjects, he said.

Japanese executives who have testified before Congress and lectured to U. S. audiences frequently have said that they obtain better results from their workers than do U. S. enterprises because of their different approach to labor relations and training. Noller said the first tour will examine some of those basic differences.

"We tend to have an authoritarian management style," he said. "In Japan, everyone is consulted, including the workers. As a result, we are more efficient in the speed of our decision making, but they are more effective in terms of carrying out their decisions. By the time they decide to do something, everybody is on board."

He said the Japanese devote more time and resources to training their workers for multiple skills, which allows them to move workers to new functions instead of laying them off as economic conditions change. Some Japanese factories are so automated that they have "virtually no workers," but they have created new jobs in designing and maintaining the automated equipment, he said.