During the fourteenth and fifteenth centuries No plays formed part of several types of entertainment, of which the most important were Sarugaku and Dengaku. The basis of No drama as it is known today was established by two Sarugaku players, Kanze Kan-ami Kiyotsugu (1333-1384) and his son Zeami Motokiyo (1363-1443),and their most important innovation was the absorption into Sarugaku of the music and songs of Kusemai, one of the many minor entertainment forms of the period. The following pages give an account of the parts played by these three entertainments in the development of NO by describing various aspects of Sarugaku and Dengaku and by showing the effect Kusemai songs had on the music and texts of Sarugaku No. The sources on which this account was based were the articles on NO written by Zeami and his son Motoyoshi, supplemented wherever possible by other contemporary material. The aim was twofold: to give a coherent account, for its own sake, of the most interesting and important period in the history of No; and, by so doing, to provide a background against which other related subjects, such as Zeami's artistic theories, may legitimately be considered. The study of No at any stage in its long history must be founded on knowledge of its form at the present time, and I should here like to thank the many people connected with NO in Japan today — players, writers, publishers, and interested amateurs — who were always ready to help me acquire something of this basic knowledge.
(ze wstępu autora do książki)