By Georgia Kiosi, Analyst KEDISA
Japan’s defeat in World War II marked the beginning of a profound transformation in its military and defence policies. From an once expansionist and militaristic empire, Japan transformed into a pacifist state with an exclusively defensive military stance.
After the official surrender of Japan to the Allied forces on September 2, 1945, the American military occupation of Japan lasted from 1945 to 1951. During that time, Japan officially rejected militarism, embraced democracy, and eagerly fought for economic growth. [1] However, the ever-evolving geopolitical environment and Asia’s regional security concerns gradually influenced and redefined Japan’s military role.
To be more specific, the most significant turning point in Japan’s military history came with the adoption of its post-war constitution in 1947, drafted under the US occupation. Interestingly, Article 9 of the constitution rejected war as a sovereign Japanese right and prohibited Japan from maintaining land, sea, and air forces.
Yet, the rising Cold War tensions, such as the Korean War (1950–1953), soon enough challenged Article 9, with the United States encouraging Japan to rearm as part of a broader regional strategy to contain the spread of communism. Therefore, in response, Japan established the Self-Defence Forces (SDF) in 1954, made up of three branches: the Ground Self-Defence Force (GSDF), the Maritime Self-Defence Force (MSDF), and the Air Self-Defence Force (ASDF). These forces, while constrained by constitutional limits, formed the foundation of Japan’s post-war defence system.
Moreover, in 1976, the United States and Japan established a Subcommittee for Defence Cooperation, a bilateral Security Consultative Committee, that laid the groundwork for the Japanese-US defence cooperation. Furthermore, in 1997, the guidelines of the cooperation were revised following the collapse of the Soviet Union and, in 2015, the US -Japan alliance was strengthened further through the release of the updated guidelines.[2] This cooperation solidified the Japan-U.S. alliance as a key element of regional security.
On December 16, 2022, a significant development occurred with the release of three security policy documents, namely, the National Security Strategy, the National Defence Strategy, and the Defence Buildup Program. These documents signalled a decisive shift in Japan’s defence posture. Notably, Japan made clear of its intention to make a full-scale contribution to the defence of Taiwan. Essentially, in the case of war across the Taiwan Strait, Japan will provide bases to the US forces fighting for Taiwan and will commit its Self-Defence Forces (SDF) troops, thus, recognizing that Taiwan’s security is an “indispensable element for the security and prosperity of the international community.” [3]
Additionally, since 1999, Japan has demonstrated its commitment to the defence of South Korea. In a wartime scenario, the SDF will assist the US forces in South Korea. In essence, the United States and Japan have already formulated a combined operation plan for the defence of South Korea, and the National Security Strategy policy document states that South Korea is in an “important geopolitical position with implications for Japan’s security.” [4]
Furthermore, the National Security Strategy policy document acknowledges the security challenges confronting Japan, noting that the “shift in the balance of power… has substantially influenced the dynamics of international politics.” [5] As a result, it identified North Korea as Japan’s primary concern in the region and described China’s actions as “an issue of concern to the international community including Japan.”[6]
In the end, Japan plans to significantly expand its defence capabilities. Japan’s military plans aim for the development of air, land, and sea based long-range anti-ship and land-attack missiles, cruise missiles and hypersonic weapons, medium and small vessels, transport ships, and transport aircraft forces and, lastly, intelligence-gathering capabilities. [7]
Ultimately, Japan’s military evolution has been influenced by the ever-changing regional threats, and Japan’s military future will likely continue to adapt in response to Asia’s increasingly complex security environment. To conclude, while maintaining its commitment to peace, Japan continues to adapt its defence strategy in response to regional threats and global geopolitical shifts.
References
Vergun, David. “U.S.-Japan Alliance Increasingly Strengthened Since End of WWII”, US Department of Defence, Nov. 7, 2024 , https://www.defense.gov/News/Feature-Stories/Story/Article/2306658/us-japan-alliance-increasingly-strengthened-since-end-of-wwii/.
Narushige, Michishita. “Japan’s New National Security Strategy”, Center for Strategic and International Studies, June 8, 2023, https://www.csis.org/analysis/japans-new-national-security-strategy.
Johnstone, Christopher B. “Japan’s Transformational National Security Strategy”, Center for Strategic and International Studies, December 8, 2022, https://www.csis.org/analysis/japans-transformational-national-security-strategy.
Endnotes
[1] Vergun, David. “U.S.-Japan Alliance Increasingly Strengthened Since End of WWII”, US Department of Defence, Nov. 7, 2024 , https://www.defense.gov/News/Feature-Stories/Story/Article/2306658/us-japan-alliance-increasingly-strengthened-since-end-of-wwii/.
[2] Vergun, David. “U.S.-Japan Alliance Increasingly Strengthened Since End of WWII”, US Department of Defence, Nov. 7, 2024 , https://www.defense.gov/News/Feature-Stories/Story/Article/2306658/us-japan-alliance-increasingly-strengthened-since-end-of-wwii/.
[3] Narushige, Michishita. “Japan’s New National Security Strategy”, Center for Strategic and International Studies, June 8, 2023, https://www.csis.org/analysis/japans-new-national-security-strategy.
[4] Narushige, Michishita. “Japan’s New National Security Strategy”, Center for Strategic and International Studies, June 8, 2023, https://www.csis.org/analysis/japans-new-national-security-strategy.
[5] Johnstone, Christopher B. “Japan’s Transformational National Security Strategy”, Center for Strategic and International Studies, December 8, 2022, https://www.csis.org/analysis/japans-transformational-national-security-strategy.
[6] Johnstone, Christopher B. “Japan’s Transformational National Security Strategy”, Center for Strategic and International Studies, December 8, 2022, https://www.csis.org/analysis/japans-transformational-national-security-strategy.
[7] Narushige, Michishita. “Japan’s New National Security Strategy”, Center for Strategic and International Studies, June 8, 2023, https://www.csis.org/analysis/japans-new-national-security-strategy.
