Turning Point Sky, Lost Land: The Fourth Defense and the Crossroads of Postwar Japan (1972-1976)

Turning Point Sky, Lost Land: The Fourth Defense and the Crossroads of Postwar Japan (1972-1976)

In 1972, a major turning point in Japan's defense policy was the "Fourth Defense Force Development Plan," or the "Fourth Defense Plan. The Fourth Defense Plan, which covered the period from FY1972 to FY1976, was a national plan to make a qualitative leap forward in Japan's defense capabilities against the backdrop of major diplomatic turning points, including changes in the international situation under the Cold War between the U.S. and the Soviet Union, moves toward the end of the Vietnam War, and the normalization of diplomatic relations between Japan and China. The Defense Agency positioned this fourth phase of defense as "not just an expansion of the military, but an improvement in quality and enhancement of its functions.

First, the Air Self-Defense Force decided to license production of the F-4EJ Phantom II, the most advanced fighter aircraft made in the United States. This was to replace aging aircraft such as the F-86 Sabre, which had been the mainstay of the Air Self-Defense Force, and to greatly enhance its all-weather interceptor capability. The introduction of the F-4 dramatically improved the Air Self-Defense Force's scrambling, or emergency launch, capability, and Japan's air defense entered a new phase.

At the same time, the Maritime SDF was also significantly strengthened. Specifically, plans were made to build large destroyers, and the concept of equipping them with the first ship-to-air missile system, the Tartar missile, and later the Sea Sparrow, was considered. This was the beginning of the Japanese version of the missile defense concept that later evolved into the Aegis Kongo class. In response to the Soviet Union's expansion of submarine warfare capability, the Japanese government also promoted the enhancement of anti-submarine operations and ASW capabilities.

In the Ground Self-Defense Force, a readiness system was established to prepare for a Soviet invasion, with particular emphasis on the Hokkaido area. This included the development and deployment of a new type of tank, the Type 74 tank, and updates to the anti-aircraft missile system, Nike J, and improved Hawk, modernizing the entire SDF, both land, sea, and air.

Such a large-scale modernization program was accompanied by an increase in defense spending, but the government of the time adhered to the self-imposed "gross national product (GNP) one percent quota" and sought a fine balance between restraining defense spending and expanding it. The Fourth Defense Plan was also an attempt by Japan, now an economic superpower, to secure the minimum necessary defense capability while maintaining the principle of a small military power.

The problem here, however, was the collapse of the aforementioned "China threat theory. With the normalization of diplomatic relations between Japan and China, the Chinese threat, which had been the primary basis for the defense buildup, was officially denied, and thus a completely different logic was needed to promote the fourth defense. The government hastily switched to the Soviet threat theory and reconfigured its defense plans with a focus on Hokkaido defense, but this was strongly criticized by opposition parties such as the Socialist Party and the Communist Party, who argued that it was military expansion without a threat.

At the time, the Asahi Shimbun editorialized, "The China-Japan rapprochement has virtually destroyed the China threat theory. If the defense buildup is to proceed despite this, it will require a completely different logic," it warned. In other words, Japan must be held accountable and self-reflective about what defense means and what national security means, rather than simply expanding its arsenal. There was a liberal sense of urgency here, as if the development of defense capability became a self-objective, it would be inconsistent with the Peace Constitution.

Thus, the Fourth Defense Review was more than just a defense budget issue; it was a national test of the self-contradiction of postwar Japan as an "economic superpower with a small military" that was being confronted in earnest for the first time. Diplomacy, defense, and public opinion were all intertwined, and in the early 1970s Japan stood at a quiet but definite crossroads.