The collections from twenty-one epochs ( Japanese 二十 一代 集 , nijūichidaishū ) are 21 anthologies of "Japanese poems" ( Waka ) compiled on the orders of different Tennō . They are further subdivided into the collections from eight epochs ( 八 代 集 , hachidaishū ), which were compiled around the end of the Heian period , and the collections from thirteen epochs ( 十三 代 集 , jūsandaishū ), from the transition to the Kamakura Time . There is also the less common term collections from 3 epochs ( 三代 集 , sandaishū ), which counts from the Kokin-wakashū .
As official, “collections compiled on imperial orders” ( 勅 撰 集 , chokusenshū ), they contrast with the much more frequent unofficial private “house collections” ( 家 集 , kashū ).
The Shinkokin-wakashū can be described as the last great waka collection, as in the following centuries the waka was increasingly replaced by newer verse forms such as renga and haiku .
