An earthquake with a magnitude initially recorded at 7.1 struck the southern Kumamoto prefecture (similar to a state) in Japan on July 28. Days ago, Japan passed the secondary capital Bill in the upper house of Parliament, a law that shows how the city continues to adapt to the frequent earthquakes it faces.Passed on July 24, this legislation allows the Prime Minister to designate a prefecture (fulfilling certain criteria) to serve vital government operations and administrative functions should Tokyo be subject to a major disaster with the ability to paralyse the city.Osaka is being considered a front-runner this time round. Previous Bills introducing an alternative capital have been rejected in 2015 and 2020. Given the country’s proximity to natural disasters, why has this Bill only been passed now and what does it specify? We Explain.A required alternative?The earthquake on July 28 marks Japan’s eighth quake of 7+ magnitude in the last decade (since 2016). The nation experiences an average of 2-3 earthquakes a day, recording over 1,500 in a single year, thanks to its geographic position at the point of collision of four tectonic plates– the Pacific, Philippine Sea, Eurasian and North American plates.Map of earthquakes measuring above 7 in magnitude since 2016 (U.S. Geological survey)Importantly, the Nankai trough– a 900-km-long submarine trench off Japan’s Pacific Coast– is the zone where the Philippine Sea plate slides below the Eurasian Plate. This creates a highly stressed interaction, known for periodically generating earthquakes.The Nankai trough marked on a topographic map of Japan (Wikimedia Commons)Today, the occurrence of a Nankai trough earthquake is considered an imminent eventuality the Japanese government has addressed– especially considering the fact that the last earthquake took place in 1944.This proximity is the justification provided for a secondary capital. Japan’s current Continuity of Government (CoG) protocols transfers command from the PM Office in Kasumigaseki to Central Command in Ichigaya and subsequently, Tachikawa’s Disaster Prevention Base in western Tokyo.Story continues below this adOn July 24, the upper house of the Japanese Parliament (referred to as the National Diet) narrowly passed the ‘Act on the Promotion of Measures to Ensure the Continuity of National and Social Functions and the Development of a Secondary Capital’ on a margin of 123 votes in favour and 121 against.The Bill commanded support from the ruling Liberal Democratic Party (LDP), its coalition partner the Japan Innovation Front (JIP) and minor opposition faction, Team Miraj.It is meant to serve as a framework statute which mandates that the central government design a basic policy within one year of the law’s enforcement to define the exact procedures and mechanisms to support this administrative division of duties. It does not name an alternative capital or shortlist prefectures directly. It does, however, set criteria that must be met to be eligible.Prefectures– totaling 47 nationally– are localised government divisions of administration just below the national government. Art.18 para 2 specifies that prefectures must gain approval from their respective assemblies prior to submitting a request for consideration. To be evaluated, a prefecture must fulfill the conditions set down in Art.2, para 3 and items under Art.18, para 1.Story continues below this adBroadly, the conditions in Art.18, para 1 state that the location, state of population and economic concentration must all meet the requirements stipulated by government ordinance i.e. they must be able to absorb national operations. The legislation suggests that cooperative agreements between a prefectural government and designated city may strengthen the local administrative structure.Upon the selection of the secondary capital, Art.19 of the Act stipulates that the central govt. shall take measures to develop transport facilities, promote economic deregulation and implement necessary tax measures to ensure private investment and utilisation of private funds. This strongly incentivises nomination by prefectures to avail of these breaks.CriticismsOne of the major talking points of the Bill has been Osaka’s seemingly lead position in securing the designation. The secondary capital was a key part of the October 2025 coalition that secured the JIP’s support of Takiachi and the LDP.Given the JIP’s roots stem from Osaka, elements of the Opposition have questioned whether the legislation is simply designed to satisfy the ruling party’s coalition partner.Story continues below this adEven opposition faction Team Miraj has questions. Their support in the Upper House was decisive in the passing of the Bill. Their support, however, was conditioned on the inclusion of mandates for digital administration and governance– forcing the ruling government to prioritise digital Business Continuity Planning (BCP) which adds a layer of digital governance to the secondary capital.Notably, the Bill does not account for an upcoming Nankai trough earthquake.ImplicationsBesides disasters, Japan’s current security environment dictates that concentrating the nation’s command structures in Tokyo might eventually lead to a critical single point of failure.The omission of military CoG protocols was also a point of debate in the Parliament given the Joint Operations Command (JJOC) – a unified HQ for the Japanese SDF. Situated in Tokyo, this base is a focal point of Japan’s ability to respond to regional crises in the Indo-Pacific. The distribution of its administrative nodes, however, contributes to Japan’s overall defence posture. It reassures allies that Japanese supply chains, markets and government functions can withstand great duress.Story continues below this adDomestically, this Bill kickstarts a decentralisation over Tokyo’s historic dominance in the country’s economy and governance. Team Mirai’s focus on digital BCP also ensures Japanese decision-making at the national level embraces ICT tech by mandating that all public services must be capable of executing all operations online with annual progress reports submitted to the Diet.