PURPOSE: To carry out warp yarn preparation of the subject yarn capable of providing woven fabrics without unevenness of gloss by forming yarn composed of single filaments having a specific structure into a sheetlike shape, bringing the sheetlike yarn into contact with a roller, applying a nonaqueous size to the sheetlike yarn and thereby homogeneously sizing the yarn.

CONSTITUTION: Yarn constructed from plural single filaments of a skin.core structure, prepared by spinning two viscose spinning solutions of different regeneration-coagulation performances (preferably 10-50% mixing degree of the spinning solutions of different kinds) and having substantially the same cross-sectional area and each cross-sectional shape of each single filament which is independently and irregularly changed in the longitudinal direction of the yarn is formed into a sheetlike shape and brought into contact with a roller. A nonaqueous size (e.g. a dry size) is then applied to the yarn to carry out preparation of the objective warp yarn.