Japan’s Quantum Moment: Why A 600-Kilometer Network Matters
John Prisco, Security CEO & founder of Safe Quantum Inc., working with data-driven companies to develop and deploy quantum-safe technologies
gettyJapan’s position in the global quantum race is becoming clearer: It may not be the country with the largest quantum-computing ambitions, but it is emerging as one of the strongest contenders in the less-hyped but equally consequential race to make quantum communications work on real-world infrastructure.
The latest signal is a new 600-kilometer quantum-encrypted network being built by Toshiba, NEC and NTT Docomo Business. The network will connect Japan’s three major metropolitan areas—Tokyo, Nagoya and Osaka—and is being developed with support from Japan’s Ministry of Internal Affairs and Communications and the National Institute of Information and Communications Technology (NICT).
The project is intended to demonstrate quantum key distribution (QKD) for high-security applications in healthcare, finance and electrical grid infrastructure, with Japan targeting broader social implementation around 2030.
The significance is less about a headline distance record than about infrastructure.
Japan is attempting to move QKD from controlled laboratory demonstrations to carrier networks and potential commercial users. This follows a 2025 Toshiba-NEC-NICT demonstration showing QKD signals multiplexed with high-capacity conventional optical traffic in an environment designed around NTT’s Innovative Optical and Wireless Network (IOWN).
And earlier this year, Toshiba, KDDI and Nokia also demonstrated QKD and post-quantum cryptography together over a commercial network carrying terabit-scale data.
Toshiba and its Japanese technology colleagues are pursuing a pragmatic proposition: Quantum security does not have to mean replacing the internet. It can mean adding quantum and post-quantum security technologies to the networks that already carry sensitive information.
Japan is certainly not operating in a vacuum. Europe is building the broader EuroQCI architecture, while individual countries are developing increasingly sophisticated test beds.
The United Kingdom demonstrated quantum-secure communications across 410 kilometers of deployed fiber between Bristol and Cambridge in 2025, combining multiple QKD approaches with entanglement distribution. European researchers have also demonstrated methods for connecting QKD test beds in Berlin, Madrid and Poznan, highlighting the region’s emphasis on interoperability and eventual cross-border networking.
The United States is taking a somewhat different path. U.S. projects include metropolitan experimental networks such as Chicago’s Illinois Express Quantum Network and Boston-area quantum-network test beds, while newer efforts are increasingly focused on connecting quantum processors and developing the infrastructure required for distributed quantum computing. In February, Cisco and Qunnect demonstrated a quantum network using existing fiber between Brooklyn and Manhattan, illustrating the U.S. emphasis on integrating quantum networking with commercial telecom infrastructure.
China, however, remains the scale benchmark. Its quantum-communications program has already produced a massive network linking terrestrial fiber and satellites, connecting five cities across a 4,600-kilometer system.
China has also accumulated a very large quantum patent portfolio specific to quantum computing, portending a future of expansive growth. According to the OECD’s 2025 analysis, Chinese applicants accounted for more than 16,000 quantum-technology patent families from 2005 through 2024, compared with about 6,400 for the United States and 2,636 for Japan. Yet the picture changes dramatically when looking specifically at international patent families, a measure more closely associated with inventions for which applicants seek protection in multiple markets: The U.S. leads there with 3,330, followed by European Patent Convention countries with 2,193 and Japan with 1,519, while China had 947.
That distinction is important for Japan. Its raw patent volume trails China and the United States, but its international patent activity is considerably stronger than the headline domestic numbers suggest.
Earlier analysis by the U.S. Center for Strategic & International Studies likewise found Japan unusually well represented among the leading international quantum-computing patent applicants, with Toshiba/Nuflare Technologies ranked second and five Japanese companies appearing among the top 20.
The broader competitive picture shows a complex three-way quantum race developing. The United States remains the leading overall quantum innovation ecosystem, according to the European Patent Office, while China has exceptional scale in domestic patenting and quantum communications.
Japan’s comparative advantage lies in industrial engineering, telecommunications infrastructure and companies capable of translating quantum research into deployable systems.
1. Commercialization: The decisive test for Japan’s 600-kilometer network will be whether banks, hospitals, utilities and other customers can use it reliably and economically—not simply whether photons can travel the distance.
2. QKD Versus PQC Or QKD Plus PQC: Japan’s own commercial-network demonstrations already point toward a hybrid model. That may prove more practical than betting the future of cybersecurity on a single technology.
3. Intellectual Property And Standards: Quantum leadership will ultimately be measured not only in qubits or kilometers, but in who owns critical technologies, supplies the equipment and defines the standards adopted by global networks.
Japan’s 600-kilometer project should be viewed as more than another quantum-network experiment. It is a test of whether Japan can turn one of its traditional strengths—world-class communications and industrial engineering—into strategic leadership in the quantum era. Leaders across the globe would do well to keep a close eye on these developments as they take shape.
Forbes Technology Council is an invitation-only community for world-class CIOs, CTOs and technology executives. Do I qualify?
