"Mounting emotional pressure" against Japan in the United States should be met by new steps in Tokyo to internationalize the home market, according to Japanese Ambassador Yoshio Okawara, who left for home yesterday after nearly five years as his country's envoy in Washington.

Okawara, 66, who is retiring from the diplomatic service after a 42-year career, much of it centered on U.S. relations, said he will tell his government and people "it is high time" for them to appreciate what is expected of Japan by the United States and other major trading partners.

"Japan has to make itself an international state," said Okawara in an interview. He added, "Japanese people are not well aware of how Japan is viewed from the outside."

Measures to open the Japanese market, which have received increasing emphasis in recent months, are more difficult to accomplish than restrictions on Japanese exports to other nations, previously the main method for alleviating trade tensions. Okawara said this shift of emphasis toward internal reforms is among the central causes of rising frustration about Japan in the U.S. Congress and among the public.

Despite the difficulties, he said, Japan has been moving to open its markets. Okawara predicted that steps will be taken in such fields as communications, pharmaceuticals and electronics.

An underlying basis for optimism about Japanese-American relations, he said, arises from growing knowledge and appreciation of Japan and things Japanese among Americans. The "information gap" between the two countries of a decade or two ago has "very much narrowed," Okawara said.

Nonetheless, he added, a difference in perception continues, especially about the Japanese market. "The Japanese government and industry share the view that the home market is open. But the U.S. government, Congress and business still view the Japanese market as closed. In their view the market-opening measures of the past few years have not really helped U.S. products find markets in Japan," Okawara said.

The departing ambassador counseled Americans to be patient as Japan adjusts to new international realities.

"Many times American people seem to be asking too much, too fast, regardless of the situation existing in Japan . . . . Reformation and drastic changes take much more time than in this country due to the necessity for consensus building," Okawara said.

He said he remains optimistic that U.S.-Japanese differences can be worked out in the long run. He described himself as "very encouraged by close, broad and deep consultations" that have developed and are the basis for "mutual accommodation" in the future.