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When the Nankai Trough or Tokyo Inland Earthquake hits, government offices and hospitals will stop functioning
In the previous blog post "Are You Still Going to Keep Using Windows and Office?" I pointed out the problems with Windows and Office.
In this post, I address cases where these flaws become fatal — the Nankai Trough earthquake and the Tokyo Inland earthquake. In these cases, I also point out the dangers of using the cloud.
Currently, in Japan, most people use Windows, and experts recommend the use of cloud services. However, this combination is, in disaster-prone Japan, already a legacy system and a structurally wrong choice. This article explains why.
In January 2026, Microsoft made it effectively impossible to use Windows offline. The authority to verify the OS's "legitimacy" has been completely centralized in US data centers.
Meanwhile, Japan is a disaster-prone country.
The Nankai Trough earthquake will cause widespread power outages and communication failures including cable cuts across western Japan. Up to 29.5 million households without electricity, three weeks for restoration in Shikoku, five weeks in Kyushu, and up to 13.1 million communication lines disrupted (Cabinet Office, March 2025 estimate).
The Tokyo Inland earthquake will stop many cloud services. Government and cloud service providers themselves will be affected. The core of the network infrastructure will also be damaged.
And the Noto Peninsula earthquake (January 2024) has already proven this is reality.
When the Nankai Trough or Tokyo Inland earthquake strikes, Windows PCs will stop working not only in disaster zones but across wide regions. Government offices will stop. Hospitals will stop. Lives will be lost.
Currently, the standard for information processing in Japanese organizations is:
This has been treated as "common sense" and "progress."
However, this combination structurally depends on three fatal assumptions:
In disaster-prone Japan, none of these three assumptions hold. The Nankai Trough earthquake will sever communications across wide areas of western Japan for weeks to months. The Tokyo Inland earthquake will damage the very core of Japan's internet infrastructure.
In other words, "Windows + Cloud" is a system designed for geologically stable land like the US mainland, and it is structurally unsuited to Japan, where disasters are the norm.
And now that AI (Claude, etc.) is widely available, it has actually become easier to handle processing locally. Setting up a Linux server with AI is cheaper and more disaster-resilient than paying ongoing subscription fees to cloud services. "Windows + Cloud" is already a legacy system.
Until now, Windows was an OS that ran on a single PC. Even without an internet connection, authentication, startup, and business operations were all completed within your own PC.
Microsoft has gradually closed off these capabilities.
| Item | Before (2025) | After (2026) |
|---|---|---|
| Communication method | Voice phone line | Data communication (web browser) |
| Required equipment | Landline / mobile phone | Another PC + Microsoft account |
| Full offline capability | Guaranteed | Effectively lost |
| Disaster continuity | High | Dependent on communication infrastructure |
The 20-year-old phone-based offline activation method was abolished in January 2026. Calling now only directs you to an online portal (aka.ms/aoh), and using the portal requires another internet-connected device and a Microsoft account sign-in.
Microsoft's official statement: "There is no way to comply other than temporarily allowing internet connection."
To use Windows offline, you need to create a "local account" during initial setup. However, Microsoft has been systematically eliminating workarounds:
bypassnro.cmd script was removed from official buildsstart ms-cxh:localonly was disabled in Insider Build 26220.6772In other words, Microsoft has clearly steered toward "using Windows offline is not supported."
In the latest Windows 11 (24H2 and later), cloud dependence has deepened further:
Word, Excel, and PowerPoint perform a "patrol authentication" with Microsoft's servers every 24 hours. If communication fails for 30 days, they enter restricted mode (view and print only; new creation, editing, and saving disabled).
Microsoft official: "Microsoft 365 Apps will not work on a computer that is completely disconnected from the internet."
In addition, Copilot integrated into Office is a cloud-based AI and stops immediately when the network is cut off. Organizations that have come to depend on AI for document creation and decisions face an "instant loss of intellectual function" during disasters.
The outcome differs depending on whether users are signed in with a Microsoft account or a local account.
PCs signed in with a Microsoft account (the current majority)
PCs using a local account
Most individual users, companies, local governments, and medical institutions sign in with Microsoft accounts. Microsoft has made this "effectively mandatory."
As a result, the moment the Nankai Trough or Tokyo Inland earthquake occurs, the vast majority of Windows PCs in disaster zones will become unusable immediately.
BitLocker is closely linked with the TPM (Trusted Platform Module) chip on the motherboard, which monitors hardware integrity. During a disaster, the TPM cannot distinguish between "an attack" and "disaster damage."
Conditions that trigger a recovery key request:
All of these are conditions that are most likely to occur during disasters such as earthquakes and power outages.
The moment the blue BitLocker recovery screen appears in a disaster zone, the PC turns into mere scrap metal. The OneDrive that should be accessed to obtain the 48-digit number is unreachable due to the severed internet.
PC drops in earthquakes, water damage from tsunamis, fire damage, power destruction from surges — these actually happen during disasters.
A normal PC (without BitLocker): You can remove the HDD/SSD, connect it externally to another PC, and rescue the data.
A BitLocker-encrypted PC: Without the recovery key, decryption is impossible even with current computational power.
In a situation where you have entrusted the keys to an "external locksmith" called the Microsoft account, and the road to that locksmith (communication infrastructure) has been closed, the data is at hand but refuses the owner's rights.
Encrypting drives is not a bad thing in itself. It is effective protection against theft and loss. The problem is who manages the keys.
LUKS has the same encryption strength as BitLocker, while the authority to manage the keys remains in the user's hands. Microsoft chose not to do that.
In the Nankai Trough earthquake, widespread power outages and communication failures including cable cuts will occur across western Japan.
| Item | 2025 Estimate | vs. 2013 Estimate |
|---|---|---|
| Maximum households without power | Approx. 29.5 million | Increase of 2.4 million |
| Communication lines disrupted | Approx. 13.1 million | 41% increase |
| Communication restoration period (Kyushu) | Approx. 5 weeks | Prolonged |
| Affected population | Approx. 60 million | About half of Japan's population |
The 41% increase in disrupted communication lines from the previous estimate is decisively important. As fiber optics and mobile communications have permeated every corner of society, the damage that physical disconnections and base station damage inflict on social functions has grown exponentially.
In the Tokyo Inland earthquake, many cloud services will stop. Government and cloud service providers themselves will be damaged. The core of the network will also be damaged.
Japan's internet structure is concentrated in the Kanto region:
In other words, when the Tokyo Inland earthquake strikes:
And this affects the entire country, including non-disaster areas.
Immediately after the earthquake, fiber optic networks were physically torn apart by ground deformation.
NTT West publicly released the "Emergency Power Depletion Outlook Map" on January 4 and 5 for parts of Wajima City and Suzu City. This proved that even when electricity is restored, the internet is powerless if relay base stations don't work.
"In the Noto Peninsula earthquake, many people initially evacuated with nothing — no wallet, no smartphone, no medication notebook, no insurance card."
— National Federation of Health Insurance Doctors Associations
Policy decisions based on normal communication infrastructure were hopelessly disconnected from the reality of extreme disaster zones.
Hospitals are a massive concentration of Windows PCs, and these are directly tied to "lives." The same structural problem exists in every field — administration, education, finance, manufacturing, logistics, and more. Here, I use medicine as an example to show its severity.
1. Electronic medical records become unusable
Cloud-based electronic medical records, even outside disaster zones, can leave doctors unable to see a single past chart due to communication failures or data center problems.
2. Loss of medication information
Treating dialysis, diabetes, or cardiovascular patients without past prescription data carries extremely high risk of medical accidents.
3. Confusion in triage
In disaster fields, identifying the injured and prioritizing treatment depends on data input/output. If this depends on Windows, system failure means complete hospital dysfunction — a logical hospital closure.
Business PCs not working → Operations are delayed (serious, but not immediately fatal) Electronic medical records inaccessible → Medical judgment itself stops → Direct risk of death
And this is not just a problem for medicine. At government offices, disaster certificates cannot be issued. At banks, payments stop. At schools, contact networks fail. At factories, production and shipping stop. The same structural functional shutdown occurs simultaneously in all fields.
Microsoft's design changes are perfect from a business logic perspective. They eliminate piracy, collect user data, and channel users into continuous payment models. However, the parameter "survival in regions where massive earthquakes occur, like Japan" is not built in.
Meanwhile, the structure on Japan's side also amplifies the risk. Data centers, submarine cable landing points, and IXs are all concentrated in Kanto, and the entire "neck" of Japan's internet is gathered at one point. The Tokyo Inland earthquake strikes precisely at this neck.
A hybrid design (combining cloud and local) is technically possible. But Microsoft has moved in the direction of intentionally and systematically eliminating offline operation.
In disaster-prone Japan, resilience must be the highest-priority requirement, with convenience and management efficiency coming after. Today's Windows has these priorities completely reversed.
Linux (Debian, Ubuntu, etc.) fully retains the "autonomy" that Windows has discarded.
1. Liberation from authentication
As open-source software, Linux requires no communication with external servers either at install time or at startup. With electricity, the OS will reliably boot.
2. Self-contained disk encryption (LUKS)
LUKS stores the encryption key in the disk header itself. The design has the user manage passwords (or a physical USB key), with no need to entrust keys to the cloud.
3. Permanent operation guarantee
Alternative software like LibreOffice does not require a "30-day check" for license renewal.
4. Realizing geographic distribution
A Linux server running in your own company or local area is affected only if disaster strikes that area. Other areas are not affected. It separates your region from the chain of data center concentration.
5. In the AI Era, Local Construction Is Easier
Until now, building local systems required specialist engineers. Contracting cloud services seemed easier.
But with AI (Claude, etc.) available, the structure has flipped. Linux installation, server configuration, business system construction — all of these can now be done by yourself, asking AI as you go. No need to hire specialists, no need for monthly subscription fees.
And a system you build yourself is completely your own. No authentication required, no subscriptions, not subject to the judgment of US corporations, and it works during disasters.
Dependence on Windows and on data centers in Kanto may be convenient and efficient in normal times. But when a major disaster strikes, the result is widespread functional shutdown and large-scale damage.
And now that AI is available, processing things locally has actually become easier. Setting up a Linux server with AI is cheaper and more disaster-resilient than contracting cloud services and paying ongoing subscription fees.
The era when "Windows + Cloud" was common sense is ending. It is a legacy system designed for the US mainland, structurally unsuited to disaster-prone Japan.
To regain a "PC as a tool" — autonomous in operation, complete in itself, able to start without anyone's permission. To regain an information infrastructure that is complete within your region. This is the most basic and most important survival strategy for disaster-prone Japan to make it through the digital age.
Migrate to Linux as soon as possible.
If you learn together with Claude, Linux isn't difficult.
For specific practical methods, please see "Learning Debian with Claude."
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