BASED AS IT IS on the Peace Constitution, Japan's defense policy is unique. Article Nine, which has remained unamended since 1946, places clear restrictions on the national military capacity, denounces any act of war, and prohibits Japan from acquiring the ability to wage war. Despite such limits on its military activities, through four defense plans over the last two decades Japan has built up a lightly armed, non-nuclear military force. Backed by the mutual security treaty with the United States, this has kept Japan out of international conflicts so far; and an important by-product is a very low military budget, which has been a key factor in Japan's spectacular economic growth. One of the biggest changes in the postwar era for Japan has been its increasing dependence on international stability as the nation emerged as a global economic power. Other regional developments have also affected Japan. The Korean peninsula, which Japanese perceive as a crucial area in their security, is still divided and the potential for conflict between the two regimes remains high. The future of Taiwan is unpredictable and will have a bearing on Japan as well. Following the withdrawal from Vietnam, U.S. policy under the Carter administration appears to espouse a reduction in American troop strength in Asia. The Soviet Union, on the other hand, has been consistently building its military strength in East Asia in both quantity and qualityenough to merit the Japanese defense minister's observation that it is *of "increasing seriousness" to Japan. Patterns now being established, especially in Asia, but in the rest of the world as well, will seriously affect the security of Japan. This article is a study of the ways in which a politically acceptable military position can be sustained in Japan. It will discuss the external and internal factors that have a bearing on that position and how Ja-