Shaded "Note that the composition of the ruling coalition may change between lower house elections, e.g. after upper house elections. Parties who vote with the government in the Diet, but are not part of the cabinet (e.g. SDP & NPH after the 1996 election) are not shaded."  ! style="background:#e9e9e9" | Parties ! style="background:#e9e9e9" | Segment ! 1996 !! 2000 !! 2003 !! 2005 !! 2009 !! 2012 !! 2014 !! 2017 ! colspan="2" | Total seats !! 500 !! 480 !! 480 !! 480 !! 480 !! 480 !! 475 !! 465  ! style="background:#e9e9e9" | Parties ! 1958 !! 1960 !! 1963 !! 1967 !! 1969 !! 1972 !! 1976 !! 1979 !! 1980 !! 1983 !! 1986 !! 1990 !! 1993 ! Total seats !! 467 !! 467 !! 467 !! 486 !! 486 !! 491 !! 511 !! 511 !! 511 !! 511 !! 512 !! 512 !! 511  Under the 1889 Meiji Constitution which took effect in 1890 and established the Imperial Diet, the House of Peers functioned as an aristocratic upper house in a format similar to the House of Lords in the Westminster system, or the Herrenhaus in the Prussian government of the time (by then a state of the German Empire). The elected House of Representatives served as the lower house of the Imperial Diet. In the Imperial Diet, both houses (and the Emperor) had to agree to legislation; even at the height of party-based constitutional government, the House of Peers could simply vote down bills deemed too liberal by the oligarchy such as the introduction of women's suffrage, increases in local autonomy or trade union rights. The government and the prime minister leading it were neither responsible to nor elected by the Imperial Diet. But the right to vote on (and if necessary block) legislation and more importantly the budget gave the House of Representatives leverage to force the government into negotiations. After an early period of frequent confrontation and temporary alliances between the cabinet and political parties in the lower house, parts of the Meiji oligarchy more sympathetic to political parties around Itō Hirobumi and parts of the liberal parties eventually formed a more permanent alliance in form of the Rikken Seiyūkai in 1900. The confidence of the House of Representatives was never a formal requirement to govern; but in fact between 1905 and 1918, only one cabinet took office that did not enjoy majority support in the House of Representatives.