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Defence in decline: Japan’s demographic impasse

Samuel Ng

Source: Official United States Air Force Website

For years, Japan has faced a demographic quagmire with birth rates consistently below replacement levels exacerbated by a rapidly ageing population. Today, there are some 123 million Japanese, but according to Japan’s National Institute of Population and Society Security Research, this number will sharply decline to 86 million by 2060 and only 50 million by 2100.

Observers have keenly pointed out the economic and cultural impacts, however, national security concerns are becoming increasingly apparent. This issue has far-reaching consequences for Japan’s defence posture, military capabilities, and its ability to effectively address security threats in its region.

Presently, the Japanese Self-Defence Force (JSDF) is predicted to be one of the world’s most effective fighting forces despite its constitutional restrictions to defensive and humanitarian missions only. However, Japan’s shrinking population may hamstring Tokyo’s ability to defend itself, let alone project power in East Asia and beyond.

With a smaller population and armed forces than its Asian counterparts, Japan may face limitations in its ability to maintain a robust defence presence in the region. This may impact its deterrence of potential adversaries and ability to respond effectively to security challenges. The lack of human resources may complicate Japan’s ability to assert sovereignty over disputed territories such as the Senkaku Diaoyu Islands, posing a direct threat to Japan’s ability to maintain its claim over these islands.

A band-aid at best

Japan’s population first began to decline in 2011. As a result, policymakers have grown the JSDF to be more capable than ever during the 2010s.

Recent Japanese defence discourse envisioned Tokyo to further increase its capabilities, outlined in its 2021 Defence White Paper, where Japan finally crossed the Rubicon by developing strike missiles to enhance deterrence. Simultaneously, Japan is also in the process of converting its Izumo-class helicopter destroyers to carry state-of-the-art F-35 stealth fighters and the additional acquisition of Aegis-equipped destroyers.

However, how long can this expansion trend continue? Although Japan’s military capabilities are improving to compensate for its demographic decline, the funding outlook for the JSDF is unclear.

Limitations, limitations, limitations

Maintaining and increasing the defence budget has its limitations. Observers have identified that the Japanese government may struggle to garner sufficient public support to increase defence spending above 1 percent of its gross domestic product. This opposition to militarism has taken an extreme tone, where in November 2014, a Japanese man self-immolated in protest of former Prime Minister Abe Shinzo’s plan to amend the constitution to allow for collective self-defence.

With the Ukraine War exacerbating the global cost-of-living crisis and subsequent economic instability, Japan’s already struggling economy is further weakened. In 2020, the country’s debt was 256 percent of its GDP, the highest ratio among all industrialised economies. This debt will inevitably grow larger as the country grows older. As the number of elderly citizens increases, the cost of social welfare, healthcare, and associated services rises alongside – all of which may divert resources away from defence spending.

The population decline is stymieing JSDF recruitment and places a hard limit on defence spending, with the crisis cited as the primary cause of the JSDF failing to meet its personnel quotas. Although the Japanese government made the controversial decision to increase the upper age limit for military recruits in 2018 from 26 to 32, the pool of eligible personnel will inevitably decrease by 30 percent over the next four decades. To add insult to injury, the JSDF has traditionally recruited from rural areas where economic opportunities are sparse. But as youth are generally the hardest hit from economic stagnation, many have moved to metropolitan areas for work, adding to Japan’s reputation as one of the most urbanised societies globally, with around 92 percent of the population in cities as of 2021.

Technology to fill the gap?

In a post-Abe era, there is a strong current against the political goal of a militarily stronger Japan. The insurmountable demographic crisis forces policymakers to consider a wide-range of solutions to uphold Japan’s national security and defence posture.

With a deficit in human resources, the Japanese government has begun shifting its focus towards investment in automated technologies, artificial intelligence, unmanned vehicles, and capital equipment purchases. These technologies are emphasised to be defensive in nature and are procured to lessen the JSDF’s human burden, and not to upend the delicate regional balance of power. However, as important as emerging technologies are, they cannot fully offset challenges Japan faces.

Women in the JSDF

The Japanese Ministry of Defence committed to increasing the share of women in the JSDF to a modest 12 percent by 2030. In 2018, women comprised only 7 percent compared with an average of 11 per cent in NATO countries.

The JSDF has had a turbulent relationship with women in its ranks, not dissimilar from Japanese society as a whole. At first, women were only allowed to enter as nurses. In 1986, Japan’s Equal Employment Opportunity Act came into effect, but it was only in 1992 that it was possible for women to become senior officers. By 1993, all occupation fields were opened, but the Japanese government barred women from serving on warships, submarines, or fighter jets, citing “motherhood” duties.

Finally in 2015, the JSDF’s aviation branch allowed women to be assigned to fighter aircraft, and in 2017, the ground force opened infantry and tank units to women. The maritime JSDF, which lagged behind, gave the green light for women to serve on submarines in 2018. In the same year, the Ministry of Defence, aiming to facilitate and increase women in the JSDF, earmarked billions of yen towards building day-care facilities and female-only areas.

However, just as in the Japanese private sector, women are subjected to disproportionate amounts of discrimination and sexual harassment. Professor Sato Fumika, specialist in gender and military studies at the Hitotsubashi University, noted that in the JSDF, “women have to adopt survival strategies centred on minimising friction in a male-dominated workplace.” Although the Japanese government aims to increase female participation in its armed forces, much more needs to be done to attract women and to provide adequate institutional support.

Reform and change

As Japan grapples with its shrinking population, policymakers must consider a holistic approach to uphold national security by taking into account the interplay between demographics, military readiness, automated technologies, and female participation. While the challenges Japan faces are complex, the nation has a history of resilience and innovation; combined with strategic planning, international and public-private cooperation, Tokyo has the opportunity to emerge stronger and more prepared to target future security and demographic hurdles while fostering a more progressive society.


Samuel Ng is currently in his final year of a dual Bachelor of Laws (Honours) and Bachelor of International Business at the Queensland University of Technology in Australia. He is also a Westpac Asian Exchange Scholar for Taiwan, previously studying at the National Chengchi University having undertaken units in Taiwanese international relations, diplomacy, and political history.



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