Japan’s political system or the pattern of governance is fundamentally, parliamentary, and broadly Westminster model.
There is a constitutional monarch, who is referred as the Emperor,who in theory chooses the PM, but the PM must have the support of the majority of the in House Representatives which here means that the parliament de facto chooses the PM.
There are two segregated houses of parliament, the House of Representatives and the House of Councillors.The House of Representatives have elections every four years and the latter House of Councillors elected in halves every three years. In the due process of electing a suitable government, the Representatives are bestowed with much more power compared to the Councillors. Since the Representatives are much in power they get the authority to choose the government. With utmost utilization of councilor’s power they can block Representatives and in the counter reply Representatives can overrule them with a proven two thirds majority. Liberal Democratic Party of Japan has been dominating the government since 1955. This makes it by and large the most successful political party in any advanced democracy in the world.
In a multi-party bicameral parliamentary representative democracy constitutional monarchy, the Emperor is the head of the state and the Prime Minister is the Head of the Government. With legislative powers vested to House of Representatives and the House of Councillors, Judicial powers are vested in Supreme Court as well as in lower courts. The fundamental rights and duties of the citizens of Japan are conferred in the Constitution. As mentioned earlier Japan in totality is a constitutional monarch with a framed system of civil law.
Japan has relatively been termed as a Flawed Democracy by The Economist Intelligence Unit where the country is also known to be a broadly functioning democracy. The several problems persist like over powerful civil service and the dominance of elite focused around the Liberal Democratic Party, bureaucracy and business. In a positive manner the civil rights are highly respected, the procedures of elections are free and fair and there is a media plurality.