The was the upper house of the Imperial Diet as mandated under the Constitution of the Empire of Japan (in effect from 11 February 1889 to 3 May 1947).
In 1869, under the new Meiji government, a Japanese peerage was created by an Imperial decree merging the former court nobility (kuge) and former feudal lords (daimyos) into a single new aristocratic class called the kazoku. A second imperial ordinance in 1884 grouped the kazoku into five ranks equivalent to the European aristocrats: prince (equivalent to a European duke), marquess, count, viscount, and baron. Although this grouping idea was taken from the European peerage, the Japanese titles were taken from Chinese and based on the ancient feudal system in China. Ità  Hirobumi and the other Meiji leaders deliberately modeled the chamber on the British House of Lords, as a counterweight to the popularly elected House of Representatives (Shà «giin).
In 1889, the House of Peers Ordinance established the House of Peers and its composition. For the first session of the Imperial Diet (November 1890âÂÂMarch 1891), there were 145 hereditary members and 106 imperial appointees and high taxpayers, for a total of 251 members. In the 1920s, four new peers elected by the Japan Imperial Academy were added, and the number of peers elected by the top taxpayers of each prefecture was increased from 47 to 66 as some prefectures now elected two members. Inversely, the minimum age for hereditary (dukes and marquesses) and mutually elected (counts, viscounts and barons) noble peers was increased to 30, slightly reducing their number. By 1938, membership reached 409 seats. After the addition of seats for the imperial colonies of Chà Âsen (Korea) and Taiwan (Formosa) during the last stages of WWII, it stood at 418 at the beginning of the 89th Imperial Diet in November 1945, briefly before General Douglas MacArthur's "purge" barred many members from public office. In 1947, during its 92nd and final session, the number of members was 373.
After revisions to the Ordinance, notably in 1925, the House of Peers comprised:
After World War II, the United States occupied Japan and undertook widespread structural changes with the goal of democratization and demilitarization, which included extensive land reform that stripped the nobility of their land and therefore a major source of income. A new constitution was also written by the occupiers, the current Constitution of Japan, in effect from 3 May 1947, which required the mostly unelected House of Peers be replaced by an elected House of Councillors.