The general term yūsoku refers refers to the ancient customs and ceremonies of the Japanese court, and the study of yūsoku extends to all aspects of ancient court life, from laws and ordinances and forms of government procedure to dress, personal ornamentation, and domestic furnishings. "yūsoku patterns," however, refer specifically to the textile designs which developed at the Heian court for use on the garments worn on ceremonial occasions.
Not a single original costume dating from the Heian period exists today. Fortunately, however, the woven textile patterns known as yūsoku patterns, with their origins in the costume motifs of the Heian period, provide the basis for an imaginative reconstruction of traditional dress. From the middle of the Heian period onward, the Japanese nobility abandoned the T'anginfluenced dress that had prevailed theretofore; clothing worn at court regained a Japanese flavor and became increasingly voluminous and multilayered. Similarly, the hōsōge patterns and animal motifs of Chinese origin that had appeared on the dyed fabrics of the Nara period gradually disappeared, and use of multicolored nishiki brocade also died out. Replacing them were solid-color silk textiles with designs expressed solely by contrasting weaves. Due largely to technical necessity, woven patterns tend to be geometrical. In order to decorate fabrics with more complex, pictorial designs, the technique of double-layer weaves was perfected. This allowed weavers to produce patterns of birds and flowers in soft, harmonious colors on