Japan’s move toward active cyber defence: a strategic shift in national security

Japan’s Liberal Democratic Party has proposed an ‘active cyber defence’ system, allowing the government to collect telecom metadata to detect and prevent cyberattacks as part of broader national security reforms to strengthen the country’s cybersecurity capabilities.
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On 10 September, the Liberal Democratic Party (LDP) proposed a groundbreaking system of ‘active cyber defence’ (Nōdō-teki saibā bōgyo) for Japan. This initiative, presented to Prime Minister Fumio Kishida by former Defense Minister Itsunori Onodera, aims to bolster national cybersecurity by allowing the government to collect and analyse metadata from domestic telecom providers. The goal is to detect potential cyber threats early and take pre-emptive actions to prevent attacks.

Onodera, who chairs the LDP’s Security Research Commission, emphasised the critical importance of this system for Japan’s national security. The proposal acknowledges the need to limit data collection to comply with Japan’s constitutional protection of ‘secrecy of communications’ under Article 21.

The push for heightened cyber defences gained momentum in April 2022, when former US Director of National Intelligence Dennis C. Blair warned Tokyo that Japan’s cybersecurity measures lagged behind its allies, especially the US. Blair’s recommendations called for Japan to establish stronger cyber leadership, create institutions akin to the US National Security Agency (NSA) and Cyber Command, and enhance collaboration with the US Joint Cyber Defense Collaborative (JCDC).

The current LDP’s proposal is a key part of Japan’s broader national security overhaul, as reflected in the revised National Security Strategy (NSS), National Defense Strategy (NDS), and Defense Buildup Program (DBP), approved by the Japanese government in December 2022. The NSS acknowledges the growing cyber threats, particularly from China and Russia, and emphasises the need for active cyber defence, the procurement of counterattack capabilities, and investment in advanced technologies like AI and unmanned weapons systems.

In the cyber domain, the shift toward ‘active cyber defence’ marks a significant change. Japan plans to create a new organisation to oversee cybersecurity policies and coordinate efforts. The Ministry of Defense will increase its cyber personnel from 1,000 to 4,000 ‘cyber warriors’ and provide training to 16,000 JSDF members over the next five years.

To implement these changes, revisions to existing laws, such as the Telecommunications Law and Unauthorized Computer Access Prohibition Law, are expected. This will enable Japan to carry out administrative interception, bringing it in line with practices in other Western nations. With these measures, Japan aims to strengthen its cybersecurity posture and safeguard critical infrastructure from growing cyber threats.