 For the lay aristocrats, the Heian court of Kyoto was the hub for the classical study of both Chinese and Japanese arts and letters, becoming a fertile ground for aesthetic theories, some of which were borrowed from China, but others emerging from more native sensitivities. The notion of reality as a self-expressive field—whether formulated in terms of the native idea of kokoro or of the activity of the cosmos-as-buddha, whether seen as permeated with the spiritual power of kami or buddhas, whether relished for the poignancy of its impermanent beauty however fleeting (as in the aesthetic of aware in Lady Murasaki’s Tale of Genji) or seen as a detached object for amusement (as in the aesthetic of okashi in Sei no Shonagon’s Pillow Book)—became a focal point for the cloistered world of the Heian court, generating an artistic sensitivity and vocabulary that became a cornerstone of Japanese aesthetics. As the classical period drew to a close, however, the cloistered worlds of the monastery and the Heian court would come under attack and philosophical innovation would need to find new contexts.