of the poem, if known. Major poets of the Kokin Wakashū include Ariwara no Narihira, Ono no Komachi, Henjō and Fujiwara no Okikaze, apart from the compilers themselves. Inclusion in any imperial collection, and particularly the Kokin Wakashū, was a great honour. Influence of Kokin Wakashū The Kokin Wakashū is the first of the Nijūichidaishū, the 21 collections of Japanese poetry compiled at Imperial request. It was the most influential realization of the ideas of poetry at the time, dictating the form and format of Japanese poetry until the late nineteenth century. The primacy of poems about the seasons pioneered by the Kokin Wakashū continues even today in the haiku tradition. The Japanese preface by Ki no Tsurayuki is also the beginning of Japanese criticism as distinct from the far more prevalent Chinese poetics in the literary circles of its day. (The anthology also included a traditional Chinese preface authored by Ki no Tomonori.) The idea of including old as well as new poems was another important innovation, one which was widely adopted in later works, both in prose and verse. The poems of the Kokin Wakashū were ordered temporally; the love poems, for instance, depict the progression and fluctuations of a courtly love-affair. This association of one poem to the next marks this anthology as the ancestor of the renga and haikai traditions. Period of cloistered rule The period of cloistered rule overlapped the end of the Heian period and the beginning of the Kamakura period. Cloistered rule (Insei) refers to an emperor "retiring" into a monastery, while continuing to maintain a certain amount of influence and power over worldly affairs, and yet retaining time for poetry or other activities. During this time the Fujiwara clan was also active both politically and poetically. The period of cloistered rule mostly Heian period but continuing into the early Kamakura period, in or around the 12th century, some new movements of poetry appeared. Imayō in the period of cloistered rule First a new lyrical form called imayō (今様, modern style, a form of ryūkōka) emerged. Imayō consists of four lines in 8–5 (or 7–5) syllables. Usually it was sung to the accompaniment of instrumental music and dancing. Female dancers (shirabyōshi) danced to the accompaniment of imayō. Major works were compiled into the Ryōjin Hishō (梁塵秘抄) anthology. Although originally women and commoners are thought to be proponents of the genre, Emperor Go-Shirakawa was