characters wrote in the story. In the story most of those waka were created as an exchange of letters or a conversation. Many classic works of both waka and kanshi were quoted by the nobles. Among those classic poets, the Chinese Tang-dynasty poet Bai Juyi (Po Chü-i) had a great influence on the culture of the middle Heian period. Bai Juyi was quoted by both The Pillow Book and Tale of Genji, and his A Song of unending Sorrow (長恨歌), whose theme was a tragic love between the Chinese Emperor and his concubine, inspired Murasaki Shikibu to imagine tragic love affairs in the Japanese imperial court in her Tale of Genji. Fujiwara no Teika Fujiwara no Teika (1162 to 1241) was a waka poet, critic, scribe and editor of the late Heian period and the early Kamakura period. Fujiwara no Teika had three lines of descendants: the Nijō, Reizei family and Kyōgoku family. Besides that, various members of the Fujiwara family are noted for their work in the field of poetry. Kokin Wakashū anthology In the middle of the Heian period Waka revived with the compilation of the Kokin Wakashū. It was edited on the order of Emperor Daigo. About 1,000 waka, mainly from the late Nara period till the contemporary times, were anthologized by five waka poets in the court including Ki no Tsurayuki who wrote the The Kana preface to Kokin Wakashū was the second earliest expression of literary theory and criticism in Japan (the earliest was by Kūkai). Kūkai's literary theory was not influential, but Kokin Wakashū set the types of waka and hence other genres which would develop from waka. The collection is divided into twenty parts, reflecting older models such as the Man'yōshū and various Chinese anthologies. The organisation of topics is however different from all earlier models, and was followed by all later official collections, although some collections like the Kin'yō Wakashū and Shika Wakashū reduced the number of parts to ten. The parts of the Kokin Wakashū are ordered as follows: Parts 1–6 covered the four seasons, followed by congratulatory poems, poetry at partings, and travel poems. The last ten sections included poetry on the 'names of things', love, laments, occasional poems, miscellaneous verse, and finally traditional and ceremonial poems from the Bureau of Poetry. The compilers included the name of the author of each poem, and the topic (題 dai) or inspiration