Frustrated by the restraints of United States-led economic sanctions against the Soviet Union, Japanese businessmen are now bent on rapid restoration of normal trade relations with Moscow.
The biggest-ever business mission to the Soviet Union is scheduled to hold wide-ranging talks in Moscow Feb. 22 to 27.
The original initiative came from the Soviets who have been holding the Japanese solely responsible for ''destroying opportunities for expansion of trade and economic cooperation,'' to quote Foreign Trade Minister Nikolai Patolichev last year.
But the Soviet position was in full accord with the desires of many businessmen here who felt they were missing out on golden opportunities to make money at a time of economic recession. They thought these opportunities were being snatched away by the sanction-busting activities of American and European rivals.
The business mission to Moscow is being led by Shigeo Nagano, president of the Japan Chamber of Commerce and also co-Chairman of the Japan-Soviet economic committee. This latter body has not met since 1979, shortly before the Soviet invasion of Afghanistan which led to the imposition of economic sanctions by the US and some of its allies.
Mr. Nagano previously had played a leading role in promoting Japanese cooperation in Soviet development of coal, gas, forestry products and other natural resources in Siberia and the Sakhalin continental shelf off northern Japan. Under strong American pressure, this cooperation was suspended, especially as some of the Japanese equipment for the oil and gas projects involved US-developed technology.
By the middle of last year, however, there were strong signs that both government and business were champing at the restraints. According to Nagano: ''The United States decided on the sanctions and in spite of the difficulties of our situation, the Japanese people agreed with this . . . which was as it should be.
''But the striking thing - if you look at the trade figures - is that whereas Japan topped the list for trade with the Soviet Union before the introduction of sanctions, it has since dropped back to fifth place behind West Germany, Finland , France and Italy.
''We took the situation seriously and cut off not only official credits but even the missions we had been sending annually to the Soviet Union till then . . . Whereas, the Europeans went ahead promoting trade with the Soviets . . . .
''Then, last November, the United States sent a 250-man business mission to Moscow - including five congressmen. Little wonder I've had Japanese businessmen knocking on my door urging us to get a mission together.''
Japan-Soviet trade has continued to grow since 1979 despite sanctions, but the business community says the rate of expansion was much less than it should have been. Two-way trade in fiscal 1981 was less than $6 billion, half the level of Japanese trade with China.
With the trade mission, the Soviets reportedly hope to win wider Japanese cooperation in Siberian development, which can be incorporated into their 12th five-year plan beginning 1986.
Mr. Nagano downplays this hope. ''Our aim is to discuss ordinary trade and existing economic relations with the Soviets . . . that is, projects already underway.''
The business mission goes to Moscow at a time when political relations between the two countries have worsened, mainly through the new Japanese government's closer defense cooperation with the United States and a Soviet retaliatory threat to site SS-20 medium-range missiles in Siberia targeted on Japanese cities.
The Tokyo government is not discouraging the business initiative. But Foreign Minister Shintaro Abe told Soviet Ambassador Valadimir Pavov recently ''economic relations alone cannot promote bilateral ties as a whole.''
This required settlement of the territorial issue (Japanese northern islands in Soviet hands since 1945) and conclusion of a peace and friendship treaty, he added.