After World War II, many Japanese looked back on the war with deep regret, and made efforts to show the international community a nation reborn. Then, when the Cold War altered the punitive nature of the initial occupation policy, and a warped postwar system was implanted as a result, Japan acted as a ''good loser'' by submitting to it.

Symbolic in the area of foreign affairs was Japan's acceptance of the role of its Self-Defense Forces and the U.S.-Japan Security Treaty, while adhering to the Constitution's war-renouncing Article 9.

It was, however, a choice made with much pain, and one which has left Japan torn between the progressive pacifist views of the Left and the traditional nationalism of the Right.

The U.S.-Japan alignment did serve to keep Japan within the international community, but it was embraced by neither the Left nor Right, each for their own reasons. In attacking the U.S.-Japan security arrangement the Left cited the Constitution, while the Right harbored discontent from a nationalistic point of view, on the grounds that it limited Japan's independence.

However, since the end of the Cold War, the dispute between Left and Right has been settled domestically by the disintegration of the Left.

Meanwhile, as the memory of war fades, frustration against the warped postwar system is growing, particularly among the younger generation. At the same time, a somewhat old-fashioned brand of nationalism appears to be reviving among the older generation. This has been the cause of friction with neighboring countries, especially on the issue of Japan's wartime history.

Is there a chance that mounting frustration against the postwar systemmight evolve into an old-style nationalism? This is an important question that will decide Japan's posture in the international community in the 21st century.

There are aspects of this question which, if examined thoroughly, will lead to the issue of whether to revise Article 9 of the Japanese Constitution. However, focusing the constitutional debate upon whether or not to revise Article 9 no longer has much meaning here. Creating a new axis for discussion is the important task for the future. Through national debate on the Constitution, Japan must redefine the U.S.-Japan alignment and paint a new image of itself, while rebuilding a balance in domestic politics.

One such attempt tries to define Japan as a ''middle power.'' Based on the U.S.-Japan alignment, postwar Japan has consistently renounced military power as a tool of political diplomacy, and has avoided taking unilateral action typical of other great powers. In that sense, it can be described as a middle power, rather than a great power.

As a middle power, Japanese diplomacy in the area of power politics, including regional security, would be based on the U.S.-Japan security alliance, but also place emphasis on playing a leading role in multilateral cooperative diplomacy.

When Japan is able to present a clear picture of itself and its diplomacy along these lines, it will become more independent from the United States. It would also make it possible for Japan to give advice, as a friend, at times when U.S. actions tend to follow a course of reckless unilateralism. Until now, because Japan has been associated with the image of a great power, a familiar pattern has been set where it would call for independent action from the United States, only to find that even a rightful demand as an expression - of its own independence would be refused. -

This pattern also applies to Japan's relations with Asia. As long as Japan's diplomatic actions are seen as those of Japan as a ''great power,'' multilateral diplomacy in Asia will face a large obstacle. Of course, in Asia, Japan is still an economic power, but its economic might can be used as an asset in pursuing multilateral diplomacy.

As Japan undertakes multilateral cooperative diplomacy based on its new self-portrait, there is one important partner in Asia: South Korea.

It is one of the strengths of Japan-South Korea relations that in Northeast Asia, both countries share common values such as democracy and a market economy, while exchanges between citizens are growing. Japan and South Korea also both have an alliance with the United States, which forms the axis of their respective foreign policies.

With this common background, both Japan and South Korea should be able to give impetus to multilateral cooperative diplomacy in Northeast Asia, a region prone to power politics.

However, such efforts on Japan's part can expect to meet considerable suspicion from South Korea, as was illustrated at conferences there when this writer spoke several times about the idea of Japan as a middle power to be - asked, at times, what Japan was plotting. One important task for Japan, in its pursuit of middle-power diplomacy, is to patiently make an appeal to South Korea, which instinctively takes guard against Japan as a ''great power.''

The Japan-South Korea partnership, which will become possible after calmly making such an appeal, will form the foundation of Japanese diplomacy's new frontier in the 21st century.

In considering security cooperation in Northeast Asia, it should be evident from logic that of the four outside powers involved in the Korean Peninsula the United States, China, Russia and Japan Japanese diplomacy - - differs from the other three, which are backed by military power.

Middle Powers

There is no set translation of the phrase "middle power" in Japanese. It is a term used frequently in international politics and foreign relations. Non-nuclear states like Canada, Australia and Germany use it to indicate their country's foreign policy posture.

In Canada the term "Middle Power-ism" has been around since the 1940s, and became a way to thinking about finding an independent diplomatic position between the United States and Great Britain.

University of British Columbia Professor Paul Evans does not take middle power to indicate the size of a country, but the "quality" of its foreign policy. It is characterized by efforts to create an order based on the concept of multilateral cooperation and founded on international institutions and rules.

Canada has crafted this kind of diplomatic posture out of concern for the harmful effect of U.S. unilateralism. This way of thinking led to the Ottawa Process and the ban on anti-personnel mines that came out of it. It is also linked to Canada's critical stance on U.S. policy toward Cuba.

In Australia, a tendency to search for "stature diplomacy" is taking root. The country considers itself a middle power in its effort to avoid following an unprincipled, U.S.-dictated line, even as it maintains the ANZUS military alliance with the United States. This way of thinking grows out of Australia's multi-racial and multi-cultural society.