This study is aimed at discovering a new sewing technique whereby Japanese yukata can be made safe from seam puckering after washing. The following experiments were conducted in this present investigation : Two yukatas, one sewn by hand, the other by machine, were made, using the same two types of thread. These samples were examined to study the phenomenon of seam puckering both before and after washing. Our findings are as follows : 1) There is no great difference in seam puckering observed between hand-made and machine-made yukata after washing. 2) However, it is clear that machine-made yukata exhibit a little less seam puckering than hand-made yukata. 3) Moreover, concering partial seam puckering after washing, our research shows that three parts of a yukata, namely, sode-guchi, sode-furi and eri-shita are more prone to seam puckering than the other parts of a yukata. Thus, this experiment demonstrates that it is clearly necessary to develop a new sewing technique that will guarantee that the three above-mentioned parts of a yukata are made safe from seam puckering after washing.