>>11242648- A deep understanding of human psychology, sociology, economics, historical dynamics and politics (in terms of scientific theories, preferably mathematical).
- A set of organizations which have substantial control over the nation's government, policies, media, intelligence community, etc.
- Highly specific information about the population (culture, history, economy, politics, etc, etc...) {Needs Data Science on steroids too}
With those things coordinated efficiently and working jointly to get a few million Japanese citizens might be possible over ten to twenty years.
On another note, why the fuck would you want to do this?