Double the Capitals, Double the Ambition?

Japan’s new sub-capital plan: regional revival, disaster insurance or the start of a mega-region?

By Andrew Stevens and Prof. Naoki Fujiwara.

The establishment of Japan’s new government in October 2024 signalled two major shifts: the rise of Sanae Takaichi as the country’s first female prime minister and the formation of a fresh coalition between the long-ruling Liberal Democratic Party (LDP) and the reform-minded Japan Innovation Party (Ishin no Kai). While Takaichi’s historic victory captured international headlines, the LDP’s new partnership – created after the Komeito Party ended its coalition role for the first time since 1999 – received far less attention overseas.

This new arrangement with Ishin, sealed to secure Diet votes for Takaichi’s premiership, may look abrupt but has been years in gestation. Takaichi’s predecessors Shinzo Abe and Yoshihide Suga spent years courting its leaders in anticipation of such a necessary alliance.  Despite its smaller government leanings, Ishin itself shares ideological ground with conservative LDP factions on constitutional revision and foreign policy – even if its political base lies firmly in the Kansai region.  

Wither Tokyo?

The regionalist Ishin grew from Osaka’s sense of marginalisation under Japan’s Tokyo-centric system. While Tokyo enjoys unique single-tier metropolitan status, Osaka – once one of two special fu prefectures under the imperial constitution – now operates like any other two-tier prefecture. The Osaka Restoration Association, founded in 2010 by outspoken Osaka governor Toru Hashimoto, sought to merge city and prefectural authorities into a single metropolis with parity to Tokyo. 

Although enabling legislation was passed by the Diet in 2012, local referendums in 2015 and 2020 narrowly rejected the plan amid concerns over costs and a perceived power grab by Hashimoto and his allies.

Despite those defeats, Ishin still controls both Osaka City and Osaka Prefecture and has continued to advance what it describes as a “virtual unification”. This has extended beyond the creation of Osaka Metropolitan University in 2022 – now Japan’s third-largest public university – to include coordinated senior personnel exchanges between the two local governments and the joint establishment of integrated policy bodies covering areas such as urban planning, port administration and industrial strategy. Together, these institutional innovations have effectively operationalised parts of the original Osaka Metropolis proposal despite its rejection at the ballot box twice.

A sub-capital enters the coalition deal

Lees noticed in the October 2025 LDP-Ishin coalition agreement is a commitment to establish a legally defined “sub-capital” to serve as a backup seat of government in the event of disaster. A taskforce will decide its scope during this parliamentary session, aiming for legislation during 2026. Though short on detail, the policy revives one of Ishin’s oldest ambitions: to secure Osaka’s place as Japan’s auxiliary or vice capital. 

The idea dates back to 2011, when Hashimoto teamed up with Tokyo’s firebrand nationalist governor Shintaro Ishihara to envisage this plan in the event of an even larger disaster than that year’s Tohoku earthquake befalling the capital.  In the following year’s general election that saw Abe sweep back to power, Ishihara and Hashimoto’s Japan Restoration Party even won 54 Diet seats as the “third force” in Japanese politics but quickly fizzled out over policy and personal differences.

Candidates assemble

So far, the new coalition partners have met once to discuss the issue, agreeing in principle that a secondary capital city is necessary for the nation. However, the issue is far from clear cut and some such as Fukuoka Governor Seitaro Hattori have suggested other less seismically vulnerable regions of Japan would act as a more viable choice, with other candidates likely to join the fray.

Osaka is not even Japan’s second-largest city by population – that position is held by Yokohama, which lies adjacent to Tokyo. By dint of its political movement, it would probably be the default beneficiary of any sub-capital plan. Its leaders argue that decentralising government functions is not just regional boosterism but prudent disaster planning in one of the world’s most seismically vulnerable nations. The timing also reflects a renewed regional confidence. As host of Expo 2025, the city is already positioning itself as Japan’s showcase for innovation, design and sustainability – a test of whether Kansai can deliver on major national projects after decades in Tokyo’s shadow.

Despite its growing national profile, Ishin remains a largely Kansai-based movement. It has gone through multiple rebrands but has struggled to replicate its regional dominance elsewhere. The sub-capital issue offers Ishin a way to scale up its agenda: a symbolic shift of state power that aligns with its identity as a reformist outsider while appealing to conservative voters dissatisfied with the Tokyo establishment.

Decentralisation or disaster insurance?

The forthcoming legislation will have to clarify whether the sub-capital is a contingency plan or a standing partner to Tokyo – and, crucially, whether Osaka’s claim is automatic or subject to wider competition among regions.  Japan’s urban geography is also shifting beneath these debates. The maglev Chūō Shinkansen, linking Tokyo with Nagoya and Osaka, promises travel times of around an hour between the two largest cities. Even with delays, it points toward a single integrated mega-region rather than a simple Tokyo-Osaka duality. In that context, the question becomes whether a sub-capital within a future mega-region still constitutes decentralisation – or merely an extension of Tokyo’s gravitational pull along a faster corridor.

Japan’s past relocations offer clues, but not a template

Japan has already trialled administrative relocation, such as the Cultural Affairs Agency’s move to Japan’s former capital Kyoto and earlier pilot projects in Tokushima for the Consumer Affairs Agency. The government also relocated part of the Statistics Bureau’s operational functions to Wakayama through the establishment of the Statistics Data Utilisation Centre. Promoted under the auspices of Abe’s signature regional revitalisation agenda, these showed that decentralisation can work symbolically, but most policy and diplomatic coordination functions still remain in Tokyo. Even partial transfers of ministerial functions are estimated to cost several trillion yen.

Dividing the Diet between cities is politically and constitutionally improbable, unless some kind of European Parliament Strasbourg-type sittings occurred occasionally. More realistic is a functional model – clustering specific competencies such as digital government, statistics or infrastructure management in Osaka while Tokyo remains the diplomatic and legislative core. This approach would disperse risk and build regional capability without attempting a full on constitutional re-write.

What Britain’s civil service shift reveals

With a long history of inter-municipal learning between the two nations, the UK’s recent experience offers relevant lessons, not least in absence of a clearly defined second city – though Osaka has recently twinned with Manchester to that effect. Over 20,000 civil-service jobs have already been moved from London to regional hubs like Manchester and Glasgow (with a target of 50 per cent by 2030), and the Treasury now operates a major multi-department campus in Darlington. The Bank of England’s recent expansion of its 200-year-old Leeds offices shows how strategic relocations can create self-sustaining clusters.  Debates on Levelling Up and its previous iterations have seen a number of proposals to relocate at least one chamber of Parliament outside of London, to either Manchester or York, brought into sharper focus with the necessary decampment required under on-going restoration works.  Japan’s taskforce will face similar decisions about what functions move, where, and why.

And Japan has been here before. The dō-shū-sei plan to replace prefectures with larger regional blocs once promised a bold decentralisation but was abandoned as unworkable by the post-2009 coalition. The sub-capital debate risks the same fate if left vague or symbolic. With coalition demands, infrastructure change and national resilience now converging, Japan has a rare window to act. The question is whether Ishin can turn its long-held regional vision into a workable national reform – or whether, like past attempts, it ends up as another unrealised blueprint.

(Sources)

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Double the Capitals, Double the Ambition?