Tokyo — Japan is pulling out all the diplomatic stops to ease the friction with the United States over trade imbalances and defense spending.
Some regard Japanese trade practices as threatening to tip off the most serious trade war since the end of World War II.
The political climate is at least troubled enough for Japan to realize it must work hard to improve its image both in Washington and in Europe, which is also colliding with Tokyo over its trade policies. By May, Japanese consulates will have held more than 100 seminars across the US to put across the Japanese point of view.
Japanese Foreign Minister Yoshio Sakurauchi makes his foreign debut in Washington March 20 to try to defuse trade-war threats and to ''forge a new political climate.''
As with those before him, Foreign Minister Sakurauchi will be going to Washington pleading for time and understanding -- at a time when these commodities seem to be in precious short supply. Speaking to reporters this week , Sakurauchi said he plans to talk to American officials, including Secretary of State Alexander M. Haig Jr. and members of Congress, from a ''broader point of view.'' He said he would not touch on trade issues and American demands for greater Japanese defense spending in any detail.
Instead Ministry officials are hoping he will be able to divert American concern over the volatile trade issue into broader and safer channels -- primarily, the overall bilateral relationship.
But they glumly admit in private that there is probably little chance of steering clear of economic-related problems. A recession-hit US alarmed by a whopping $13.4 billion trade deficit with Japan is impatient for Tokyo to correct the imbalance.
Prime Minister Zenko Suzuki's special envoy Masumi Esaki visited Washington last month in an effort to convince anyone who would listen that Japan had done all it could to reduce its massive trade surplus with the US. But all he got was confirmation Americans won't accept such self-congratulatory claims. Esaki is now on a similar mission to Europe.
Mr. Sakurauchi certainly is not carrying any dramatic new initiatives in his briefcase, apart from a message from Prime Minister Suzuki to President Reagan urging the US administration not to follow a ''backward looking policy'' on trade issues (code for protectionist measures).
Among the Foreign Ministry's priorities are relaxation of Japanese import quotas, especially on agricultural products, expansion of tobacco imports, possible increase in tariff cuts, improvement of trivial and time-wasting import inspection procedures, and various issues in the services and financial fields.
The various points which the Japanese Government has put forward to ease trade frictions have cut little ice with American businessmen. There is, for example, considerable disappointment here at the lukewarm US and European reaction to the government's decision in January to dismantle 67 identifiable ''non-tariff barriers'' to imports as well as some simplification of inspection and licensing procedures of imported goods.
In Tokyo, this was pictured as throwing open wide the gates of the Japanese market to a flood of foreign products. No longer could the government be accused of unfairly shielding local business from foreign competition.
The US is also urging Japan to decrease its exports. A main sore point is Japanese cars, which are hurting the floundering American aulomobile industry.
Compounding the difficulty in American eyes is that Japan spends less than 1 percent of its gross national product on defense. This is contributing to a rising tide of US congressional and public concern that Japan is getting a ''free ride'' at taxpayers' expense.
But the Japanese feel that the US has contributed to current tension. There is irritation, for example, over the feeling that American business concerns make little effort to understand the Japanese business practices. They point to such companies as Motorola, which has used long-term planning, patient market exploration, and strict quality control to win considerable success in penetrating the Japanese electronics market.
Japan is inhibited in trying too hard to meet US objections by potential opposition at home, where the economy is also slowing down. Japanese farmers bitterly oppose removal of import quotas on key items like beef and orange juice. Japanese officials have already warned the Reagan administration that offending the rural lobby would be political suicide. The majority of ruling Liberal Democratic Party members of parliament keep their seats mainly because of the farm vote.