How is Japan’s prime minister chosen?

In Japan’s parliamentary system, the prime minister is formally appointed by the emperor after being designated by the Diet, the country’s national legislature.51

The selection process typically functions as follows:

• Designation: The Diet, which consists of the House of Representatives and the House of Councillors, designates the prime minister. In the event of a deadlock between the two houses, the vote of the lower house takes precedence.23
• Party Leadership: Because Japan is dominated by its political parties, the selection of a prime minister is often determined by the internal leadership contests of the ruling party. Major elections frequently serve to confirm which factional leader within the dominant party—such as the Liberal-Democratic Party—will assume the premiership.4
• Formal Appointment: Once designated by the Diet, the prime minister is officially appointed to the position by the emperor, who acts as the symbolic head of state.51

The prime minister leads the cabinet, which holds executive power, and must maintain the confidence of the House of Representatives to remain in office.1