Yū 木綿 was a type of cloth made from the bark of the Japanese paper mulberry, or kōzo 楮 tree, and used in religious rituals. In ancient times of trouble, there was a ceremony whereby cockerels garlanded with yū would be taken to the four boundaries of the capital to drive away evil influences. Hence the term yūtsukedori, literally ‘bird with yū attached’ came to be used as a poetic term for a cockerel.