Abstract
The food-sufficiency rate minimizing total costs and maximizing the food-reserve rate depends significantly on difference between domestic and foreign costs. The origin of the cost difference is an economic-geographic problem. The cost difference varies with foreign exchange rates. Stakeholders on food importation into Japan prefer larger difference between Japanese and foreign production costs. Thus, they prefer stronger yen. Unfavorable to them, however, yen could be weaker, unless Japan became an abroad investing state or exported products unable to be made out of Japan with international competitiveness.
