The Nijūichidaishū(二十一代集,Collections of the Twenty-One Eras) are Japan's twenty one imperial collections (chokusenshū) of waka poetry written by noblemen. The following texts listed in chronological order constitute the Nijūichidaishū:
The Hachidaishū(八代集) are the first eight collections, in which the first three collections are the Sandaishū(三代集). The Sandaishū provided both the language and organizational principles for the rest of the anthologies thereafter. They are: