Curated "Japanese Common Passwords" database

Implementation tip: Do not block every single entry (e.g., tokyo is too common as a substring). Instead, block exact matches and fuzzy variants (leetspeak, reversed).

or similar), and common surnames (e.g., "Sato," "Tanaka") coupled with birth years are standard. Cultural References

The frequency of updates will shift from annual to quarterly as automated combo list generators become AI-assisted.

Current Japanese password trends as of April 2026 show a significant gap between security best practices and common user habits. Recent studies, including a January 2026 report in Springer Nature