Zeami`s 『遊楽習道風見』 Yūgaku shūdō fūken.
When Zeami is asked what it is that makes waka so effective, he answers, the “realm of peerless charm.” This "realm of peerless charm," he explains, is exemplified in the following waka.
In the Shudōsho『習道書』, Zeami speaks about the structure of the day-long plays, which are divided into five parts-- 1 (jo), 2-4 (ha), and 5 (kyū). He points out that there should be some leniency in the transition between "ha" and "kyū."“The artistic skill of truly seasoned performers is doubtless manifested under just such trying circumstances,”he writes.
And, finally, in "The Three Elements in Composing a Play" ("Sandō" or "Nōsankusho"), Zeami hands down a secret transmittance to his son, Motoyoshi. The work was written in 1423. In it he discusses the three elements of Nō-- the seed (“the choice of subject based on appropriate traditional sources”), the construction ("jo," "ha," and "kyu" form), and the composition (the appropriate words to suite the three styles).
While catharsis is a central component to dramatic function in the West, "kaimokukaibun" 開目開聞 , or the“opening the ears and eyes,”is the "goal" of theater in Japan. "Kaimokukaibun" can be likened to the sudden "satori" of Zen, only that it is aroused from an external rather than internal stimulus. Zeami describes it as the moment when “deep sensations inherent in the play are suddenly experienced in one moment of profound exchange [between actor and audience]” (158). Zeami refers to the "flower" that exists within the work, but which is “opened”in the audience, triggering "kaimokukaibun."
Zeami seems to accept the idea that aesthetic preferences are determined mostly by social factors, rather than being universal or formulaic. “The decision as to whether a play is good or bad," Zeami explains, "cannot be made by the actor himself . . . There is no way to escape from the criticism of the world at large” (161).
Finally, art must be effective, and its value is judged by its efficacy: “A play must always be written with the basic principle of producing the seed that leads to a blooming of the Flower” (161).