The term 'Japa'drawn from the Yoruba verb meaning to flee or escapehas transcended colloquial usage to become the most diagnostically accurate descriptor of a structural demographic crisis confronting post-2020 Nigeria. This paper undertakes a comprehensive, multidisciplinary analysis of the phenomenon, integrating macroeconomic data, migration statistics, geopolitical context, and psychosocial research to construct a full account of why Nigerians are leaving, where they are going, what they encounter when they arrive, and what remains in the wake of their departure. The analysis is organised around six principal pillars