Waka poetry had a history of approximately 700 years from the latter half of the eighth century when Man'yo shu was completed to the middle of the fifteenth century when Shinshoku-kokin waka shu, the last official anthology by the imperial order, was compiled. Moreover, waka was kept alive until the early modern era.
The reason for such sustainability can be found in classicism in medieval waka, established by FUJIWARA no Tameie (1198-1275). Tameie developed a method of reusing old poetry and fixed the compositional idea of mezurashi. He valued the method called koka wo toru, which means reusing old words without representing the content composed in the old poem, and found an unexpectedness on construction of old words.
In the contemporary research on waka, Tameie's classicism is often regarded as "pseudo-classicism" and despised in terms of creative value attached to the composition. From the viewpoint of collective composition, however, the pseudo-classic aspects have the significance of extending poetic construction by constantly renewing the distribution of hackneyed phrases. Tameie's pseudo-classicism enabled waka poetry to be a sustainable system.