Kei-En era (Katsura-Saionji era) (桂園時代)

Kei-En era (or Kei-On era) was the 8-year period from 1905 to 1912 during which Taro KATSURA, who belonged to the faction led by Aritomo YAMAGATA of the Imperial Japanese Army, and Kinmochi SAIONJI, who assumed the position of president of Rikken seiyukai (a political party) as a successor of Hirobumi ITO, gained power alternately. Kei-En' (桂園) was the combination of Kanji (Chinese characters) '桂' and '園' contained in their names.

In the Kei-En era, bureaucrats and military typified by Katsura and a leading political party Rikken seiyukai typified by Saionji built a collaborative system called 'emotional agreement' and they alternately served as the prime minister (In the meantime, there was a move to field Masayoshi MATSUKATA, Gonbei YAMAMOTO and Tosuke HIRATA as prime minister, but none of them had stronger foundations of administration than those of the two, so they were forced to give up). This era is said to have been politically stable, and both the 10th general election of members of the House of Representatives and the 11th general election of members of the House of Representatives were held at the expiration of terms of office during this period. Only in this era, general elections at the expiration of terms of office were held twice in a row in the history of Japanese constitutional government.

In addition, the word 'Kei-En' has an another meaning, a name of a school of waka poetry. (the Keien school founded by Kageki KAGAWA, who was a kajin (waka poet) in the late Edo period. Keien was Kagawa's pseudonym.)
The Keien school was a conservative school which valued tradition such as innocuous "Kokin Wakashu" (A Collection of Ancient and Modern Japanese Poetry) against venturous modern tanka which was coming into fashion at that time. Relating its innocuousness to the cozy relationship between Katsura and Saionji, the period was named Kei-En era.