June 5, 2026
TOKYO – The Japanese government and some domestic financial institutions have gained access to Claude Mythos, the latest artificial intelligence model developed by U.S. startup Anthropic PBC.
The system’s capability to identify software vulnerabilities — which sent shockwaves through the industry upon its April debut — is expected to advance further on a global scale.
The government is moving quickly to bolster its cyber defenses by proactively leveraging such cutting-edge AI.
Anthropic announced Tuesday that it would expand access to Mythos to about 150 organizations across more than 15 countries. The Japanese government and several domestic financial institutions are included in this expansion, according to the government.
Anthropic previously restricted Mythos access to major U.S. tech giants and other select entities out of deep-seated concern that the technology could be exploited in the wrong hands.
“I welcome the expanded access for like-minded nations. The fact that the door has opened is a major step forward,” digital minister Hisashi Matsumoto told reporters at the Prime Minister’s Office on Wednesday.
Ahead of the access, the National Cybersecurity Office will collaborate with relevant companies and IT firms to implement program fixes.
While critical infrastructure sectors facing high risks of cyberattacks span 15 industries — including electricity and water supply— the government has not disclosed whether companies outside the financial sector have been granted rights to access Mythos.
Former digital minister Masaaki Taira spoke to reporters on Wednesday after meeting with Anthropic executives visiting Japan. Taira urged the government to consider how to extend the coverage of the technology across critical infrastructure.
In the realm of cyber defense, OpenAI has already signaled its intent to supply Japan with its own cutting-edge model, rivaling the capabilities of Mythos. The government is moving to ensure it secures access to the latest AI technologies from a broad range of such developers.