A second imperial ordinance in 1884 grouped the kazoku into five ranks equivalent to the Europeanprince (or duke), marquis, 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.
all imperial princes (shinnō) and lesser princes of the imperial blood (ō) over the age of twenty
all princes and marquis over the age of 25 (raised to age 30 in 1925)
150 representatives elected from the ranks of counts, viscounts, and barons over the age of 25 (raised to age 30 in 1925), for seven year terms
150 additional members nominated by the Emperor, in consultation with the Privy Council
66 elected representatives of the 6,000 highest taxpayers, for seven year terms.
For the first session of the Imperial Diet (1889–1890), there were 145 hereditary members and 106 imperial appointees and high taxpayers, for a total of 251 members.
With the creation of new peers, additional seats for members of the former Korean aristocracy and five seats for representatives from the Gakushuin Peer's School, membership peaked at 403 seats by 1925. In its 92nd and final session, the number of members was 373.