The Kokinwakashû (or the Kokinshû for short), the 'Collection of Japanese Poetry Ancient and Modern', was the first of the 21 anthologies of waka compiled at imperial command (chokusenshû). The idea of an imperial waka anthology as a 'modern' successor to the Man'yôshû was first mooted by Emperor Uda (867-931; r. 887-897), and eventually commissioned by Emperor Daigo (885-930; r. 897-930). He gave the commission to Ki no Tsurayuki, Ki no Tomonori, Ôshikôchi no Mitsune and Mibu no Tadamine, who chose about 1,111 poems, completing the anthology between 915 and 920.
The collection is principally one of tanka, with only a few poems in other formats, and follows the pattern of the Man'yôshû by being divided into 20 books. A new development, however, is that all the poems in a particular book are on a set poetic topic, as follows:
The collection, therefore, divides into two halves, the first beginning with poems on the most important topic, the seasons, and the second with the next-most important, Love. This 20 Book format was to set the model for the majority of future collections, as was the decision by the compilers to include both 'ancient' and 'modern' waka in the anthology.
The Kokinshû also has two prefaces: a Japanese one written by Ki no Tsurayuki and a Chinese one by Ki no Yoshimochi. Tsurayuki's preface is regarded as being the first work of Japanese poetic criticism, setting out criteria for judging poems, giving terminology and making suggestions about poets who were to be regarded as superior. In particular, he mentions the 'Six Poetic Sages' (rokkasen): Archbishop Henjô, Ariwara no Narihira, Fun'ya no Yasuhide, The Monk Kisen, Ono no Komachi and Ôtomo no Kuronushi.
The principal poets of the collection (those with more that 5 poems included) are: Tsurayuki (102), Mitsune (60), Tomonori (46), Tadamine (36), the Monk Sosei (36), Narihira (30), Ise (22), Fujiwara no Tomoyuki (19), Komachi (18), Henjô (17), Kiyowara no Fukayabu (17), Fujiwara no Okikaze (17), Ariwara no Motokata (14), Ôe no Chisato (10), Sakaoue no Korenori (8).
It is difficult to overstate the influence of the Kokinshû on subsequent waka: its organisation, to a large extent, determined the organisation of later anthologies, its topics became regarded as the only appropriate ones for poetry and its imagery became the source on which most later work was based. The primacy it accounts to the seasons is still the case in modern haiku, while the progression of its poems influenced the development of renga. Similarly, the ideas laid out by Tsurayuki in his preface formed the basis for the majority of Japanese poetic criticism until the modern period.
Nevertheless, the anthology has been heavily criticised in recent times for being overly influenced by Chinese forms and ideas, and lacking the freshness and directness of Man'yô poetry. This is true to some extent, but it is also the case that it was the first anthology compiled when there was an awareness that there was such a thing as waka, Japanese poetry (yamato uta) which was somehow different from the Chinese poetry (kara uta) the court had brought in from overseas, and that it contains numerous fine examples of lyrical expression.