As the Cold War drew to a close, Japanese politicians and the public underwent a change in mindset regarding their country's Self-Defense Force (JSDF) and the Japan-U.S. alliance. Japan's capacity to defend itself and the alliance were no longer eschewed as being harmful or capable of dragging the nation into unnecessary warfare. After the end of the high-tension East-West confrontation under the Cold War framework, the Japanese became gradually aware that Japan's military and the alliance were instruments that served to ensure their security. Nevertheless, they did not overvalue the importance of these two tools. Rather, Japan took a whole-of-government approach to achieve its national security interests, and in this way established its national security policy and institution by the end of the Heisei era.
　Reiwa-era Japan is exposed to a rapidly changing and increasingly acute security environment. This includes the competition of different worldviews and models of political governance; technology-driven challenges involving cyberspace and outer space; a rapid shift in the balance of power in traditional physical domains, in particular at sea; and non-traditional challenges, not excluding natural disasters. As Japan faces growing challenges, however, its resources are much more limited than before.
　In order to ensure its national security in this challenging environment, Japan should establish a new national security strategy to mobilize all the instruments of its national power in a coherent, effective and efficient fashion. The role of JSDF and the Japan-US Alliance should be redefined clearly in this strategy.

1. Japan's National Security Accomplishments in the Heisei Era

　The development of Japan's national security policy after the end of the Cold War was remarkable. Operations-related measures include, inter alia, legislation to enable Japan's participation in UN-sponsored peacekeeping and the subsequent dispatch of troops to Cambodia in 1992; the redefining of the Japan-US Alliance in 1996 and a subsequent renewal of the Guidelines for Japan-US Defense Cooperation in 1997; the 2001 Anti-Terrorism Special Measures Law enacted in response to the September 11 terrorist attacks and the subsequent dispatch of naval ships for refueling operations on the Indian Ocean; the 2003 legislation for war contingencies, including armed attacks; the 2003 Law Concerning Special Measures on Humanitarian and Reconstruction Assistance in Iraq and the subsequent dispatch of troops, the 2009 Anti-Piracy Measures Law and subsequent counter-piracy operations in the Gulf of Aden; and a reinterpretation of the Constitution with regard to the use of force in 2014 and a series of laws to put this new interpretation into practice in 2015. These developments have contributed to the enhancement of the role JSDF holds in ensuring national and international security.
　In the meantime, the National Defense Program Guidelines (NDPG), which outlines the policy framework for defense architecture, went through frequent revisions. It was revised in 1995 to adapt to the post-Cold War era. It was renewed in 2004, in the aftermath of the September 11 attacks, to reflect concerns about international terrorism. It was revised again in 2010 because of the region's shifting power balance, and in 2013 to squarely face the changing balance and because of an administration change. Finally, it underwent a revamp in 2018 so that Japan could counter the increasingly acute and uncertain security environment. Accordingly, the guiding concept for JSDF buildup was changed from "Basic Defense Force" to "Dynamic Defense Force", "Dynamic Joint Defense Force," and then finally to "Multi-domain Defense Force."
　As the Cold War came to a close, Japanese politicians and the public underwent a change in mindset regarding their country's Self-Defense Force (JSDF) and the Japan-U.S. alliance. Japan's capacity to defend itself and the alliance were no longer viewed as something that would expose Japan to danger, or capable of dragging the nation into unnecessary warfare. Meanwhile, nearby regional conflicts nearby such as the first North Korean nuclear crisis in the early 1990s and the 1996 Taiwan Strait crisis, as well as domestic contingencies such as the Great Hanshin earthquake in January 1995 and the Tokyo Sarin Attack in March 1995, made the public more security-minded. After these incidents, the Japanese gradually gained awareness of JSDF's and the alliance's importance in ensuring their security.
　Nonetheless, they did not overrate the importance of these two instruments. Japan took a whole-of-government approach in aiming to achieve its national security interests. Maneuvering the nation's relationship with China, dealing with North Korea's nuclear and missile ambitions, managing the Japan-U.S. alliance in the age of a rising China--all of these issues required a whole-of-government approach. JSDF's role had to be placed appropriately within Japan's overarching security strategy to shape an international environment favorable to the nation's security interests. For this reason, the government established its first-ever National Security Strategy in 2013, aiming to squarely face the volatile and uncertain security environment.
　The fundamentals of Japan's national security policy were implemented in the Heisei era. The Heisei era is also when the concept of "Asia-Pacific" started being commonly used as a way to integrate the US and Australia into Asia. Japan's defense capability and the Japan-U.S. Alliance became integral to Asian-Pacific security. A question is if the groundwork constructed in this period will continue to be relevant in the present and in the future.

2. Japan's Current Security Challenges at the Beginning of the Reiwa Era

　The development of Japan's national security and defense policy was not proactive; it was in fact a passive reaction to a changing outside environment. The developments were also incremental without a clear outlook. This is why it started with international cooperation such as peacekeeping, then dealt with the enhancement of the tools for alliance cooperation, and then finally addressed mechanisms for coping with the most important challenge (i.e. armed attacks against Japan) instead of vice versa.
　Now that Japan is back as a growing economy and a dependable U.S. ally, its power in the international community is evolving. As a nation which has long reaped substantial benefits from the existing international order, and as a maritime nation on the periphery of the Asia, where China occupies a considerable part, Japan is in a position to utilize its power to advance the global and regional order in a more proactive manner.
The international order Japan has benefitted from is eroding. The underlying causes are the competition of different worldviews ("the rules-based liberal order" and "a community of common destiny for mankind") and the competition of different models of governance (liberal democracy and digital authoritarianism). Not only Japan's choice but also its real effort to implement the choice is increasingly critical to international security and to Japan's own survival and prosperity.
　When Japan reinterpreted its Constitution and declared that it could exercise the right to defend other countries, it was at a time when Japan's own territorial integrity and sovereignty were at stake because of provocative actions by China and North Korea. Nonetheless, the new legal tool for the exercise of its military power remains highly relevant because of the highly connected nature of today's international community. In other words, Japan's own national security is inseparably linked to global and regional stability. The reinterpretation of the Constitution and the security legislation are tools that allow Japan to contribute to the stability of the globe and of the region.
　The connected world has brought another type of challenge to the international front. Although regional players are mainly fighting in traditional physical domains, in particular at sea, the new strategic domains such as outer space and cyberspace have also become grounds for competition and governance. International terrorism continues to be a common concern for the peace and prosperity of the region. Natural disasters including climate change are increasingly pressing issues , and international cooperation to address natural disasters, to which Japan is geologically and geographically prone, is a serious security challenge.
A serious question for Japan is whether it has enough resources to cope with such diverse security challenges. Its economy is in better shape but remains weak. The fiscal condition is worse. Its population is shrinking and rapidly aging.
The right answer to these difficult questions must be articulated and presented to the Japanese public and to the international community in a transparent manner.

3. Outlook for the Future

　The global and regional order is in flux; its uncertainty is increasing. Does the wavering of the order mean that it will undergo a fundamental restructuring, or will it simply be another round of adjustments? Nobody knows the answer for sure. It is a pressing question for all the members of the international community. The answer may depend on the side one is on: for or against the existing order. In this critical moment, Japan, as a responsible member of the international community, must reach its conclusion together with its alliance partner: the U.S.
　The Japanese government provided a portion of its answer by establishing the new NDPG in December 2018. The main objective of the NDPG is to define the roles and missions of JSDF and to accordingly establish the goal for defense force buildup; thus it is basically of a balance-of-power approach focused on military defense.
Japan's 2013 National Security Strategy is still intact; however, it is based on the security environment of more than five years ago. It is a well-organized expression of the group of security measures that existed at the time of its creation, yet does not fully address the huge flux and decline of the international order Japan currently faces.
　The new concept of the "Indo-Pacific" must be addressed as well. Although the decades-old concept of "Asia-Pacific" remains alive, the newer concept reflects India's rise as well as the significance of connecting of the two oceans in ensuring the security and prosperity of the region.
In order to ensure its national security in the challenging Indo-Pacific environment, Japan should establish a new national security strategy to mobilize all the instruments of its power in a coherent, effective and efficient fashion, generating synergy of all its security efforts. The new strategy should define clearly the vision for a Free and Open Indo-Pacific (FOIP) and elaborate on how it will be achieved. The defense capability Japan will achieve in accordance with its 2018 NDPG should be embedded in the strategy. The role of the JSDF and the rationales of the Japan-U.S. alliance must also be redefined in a clear-cut fashion.
　Strategy is about where we should go and how we will achieve it. It is a declaration of Japan's will to shape the international order. Japan needs a new strategy to direct itself in this acute, uncertain, and rapidly changing environment.