Twill weave with diagonal rib. Two twills of differing diagonal direction or pitch create a damask, while interrupting the twill diagonal with longer floats forms a liseré pattern. In the Shōsō-in, aya refers primarily to monochrome textiles of degummed silk with a repeat pattern in a twill that contrasts with another twill or with a plain-weave foundation. See Twill damask.