The 
Diet of Japan consists of two parts: the "House of Councillors" (informally referred as the upper house) and the "House of Representatives" (informally referred as the lower house). Modelled after the 
British Parliament, the leader of the country is the Prime Minister, majority leader from the House of Representatives.  The House of Councillors is largely ceremonial, and carries little weight in political matters.
The offical name is The National Diet of Japan or Kokkai (国会);
On February 11, 1889 the Meiji constitution was adopted paving the way for the first meeting of the Diet in 1890.
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