The are Japan's

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

 twenty one imperial collections (anthologies

Anthology

An anthology is a collection of literary works chosen by the compiler. It may be a collection of poems, short stories, plays, songs, or excerpts...

) of Japanese poetry

Waka (poetry)

Waka or Yamato uta is a genre of classical Japanese verse and one of the major genres of Japanese literature...

 written by noblemen. The following texts listed in chronological order constitute the Nijūichidaishū:

The are the first eight collections, in which the first three collections are the . The Sandaishū provided both the language and organizational principles for the rest of the anthologies thereafter. They are:

• Kokin Wakashū
• Gosen Wakashū
• Shūi Wakashū
• Goshūi Wakashū
• Kin'yō Wakashū
• Shika Wakashū
• Senzai Wakashū
• Shin Kokin Wakashū

The are the later thirteen collections. They are:

• Shinchokusen Wakashū
• Shokugosen Wakashū
• Shokukokin Wakashū
• Shokushūi Wakashū
• Shingosen Wakashū
• Gyokuyō Wakashū
• Shokusenzai Wakashū
• Shokugoshūi Wakashū
• Fūga Wakashū
• Shinsenzai Wakashū
• Shinshūi Wakashū
• Shingoshūi Wakashū
• Shinshokukokin Wakashū

Note that the Shin'yō Wakashū

Shin'yo Wakashu

The is a Nanboku-chō period collection of Japanese poetry compiled by Munenaga Shinnō ca. 1381. Although commissioned by Emperor Chōkei of the Southern Court, it is not included in the Nijūichidaishū, i.e., the twenty-one imperial anthologies for political reasons – the "official"...

—although an imperial anthology of Japanese poetry—is not included in the list of twenty one collections.