Unlike other constitutional monarchs, his function is defined as entirely representative and ceremonial in nature, without even a nominal role in government. He is limited to acting in matters of state as delineated in the Constitution, and even in those matters, he is bound by the requirements of the Constitution and the binding advice of the Cabinet. For instance, while he formally appoints the Prime Minister, he is required to appoint the person designated by the Diet, without the option to decline appointment.