Reporting on cyberattacks against Japanese entities rose 48% between Q2 and Q3 2026, encompassing ransomware, exploitation of vulnerabilities, credential leaks, and service disruptions. Significant incidents exposed millions of customer records and disrupted operations across multiple sectors, with attacks on shared service providers extending the impact to downstream organizations. Further incidents in October 2026 indicate that these trends have persisted into Q4. This report examines potential contributing factors, including demand for Japanese personal information, legacy systems, software vulnerabilities, weak API controls, and AI’s likely role in lowering technical and language barriers. New incident-reporting requirements under Japan’s Active Cyber Defense (ACD) law, effective October 1, may further increase the number of disclosures of incidents affecting Japanese organizations.