In japan, the executive head of state is the emperor. his role is only symbolic, however; the prime minister is the head of government and holds true executive power. the prime minister is elected by the majority party of the diet—japan's legislature. 10. how does the japanese government guarantee that its citizens are represented? citizens elect the members of the diet. the prime minister is elected by citizens. the emperor meets the needs of his citizens. executive power is divided into two equal parts.