Japan's Nursing Workforce as Health System Security: From Silent Brain Drain to Brain Circulation.

Japan's nursing policy has long been shaped by an implicit "closed-loop" assumption that language and licensure barriers will keep most nurses in a domestic labor market. Ten years after the Health Care 2035 vision was introduced, this assumption is weakening. Currency depreciation and widening international wage differentials, technology-enabled reductions in language-related preparation costs, and increasingly active global recruitment are together making outward mobility a realistic option for highly skilled nurses. Yet Japan lacks robust reintegration pathways for nurses who return with international education or experience, creating "brain waste" and accelerating loss of clinical leadership. This Opinion argues that nursing retention has become a national health system security issue directly affecting patient safety and system resilience rather than being a problem solvable within individual hospitals. Japan should pivot from ad hoc retention to an explicit "brain circulation" strategy, enabled by three policy levers: reimbursement mechanisms that make advanced nursing practice economically legible within the fee schedule, clinical-academic joint appointments that create landing zones for returnees, and scope-of-practice reform aligned with international standards.