This report was prepared to compare and analyze the testing method and classification of winding test in Korea to that in Japan, and the obtained results, which had been carried out, in Korea, from Sep. to Nov. in 1968 and in Japan through June in 1968, was as followings. 1. In Korean raw silk, (21 D.) the average number of breaks on winding test showed 5.91 by Korean Method but showed 8.6 by Japanese method and the latter increased to 2.7. On the other hand in Japanese raw silk, it showed 3.6 by Korean method but 4.7 by Japanese method and the latter increased to 1.1. (See Table 2,3) 2. It was seemed the tendency that the lot distribution of breaks number in Korean silk was mostly concentrated to the breaks No. 3,4 and 5(48％) by Korean method but in case of Japanese method to the breaks number 5,6 and 7(36％), and the tendency that the concentration depended mostly on the increased number of breaks. In Japanese raw silk, it was seemed the tendency that the lot distribution of breaks number was mostly concentrated to the breaks number 1. 2, and 3 (55％) by Korean Method but in case of Japanese Method to the breaks number, 2,3 and 4(50％) and the tendency that the concentration was as similar as the above. (See Table 2,3) 3. It was found the tendency that the distribution of breaks number during the open winding test was mostly concentrate red to the average number of breaks not only in Korea but in Japan. The rate 0: non-breaks, however, showed 43％ of Japan, to 7％ of Korea. (See Table 4) 4. Applying Table 1,2 to the Classification of Korea and Japan, the class distribution by Korean table showed 68％ of class 1(6), 22％ of cl ass 2(10) and 9％ of class 3(15) in Korean silk, while that by Japanese table showed 13％ of class 1(4), 56％ of class 2(10) and 29％ of class 3(18). And then the testing result to be class 1 or 2 by Korean table was. degraded from class 1 to class 2 of 55％ and from class 2 to class 3 of 20％ down. In Japanese silk, however, the class distribution by Korean table showed 85％ of class 1 (4), 10％ of class 2(10) and 5％ of class 3(18) but that by Japanese table showed 60％ of class 1(4), 33％ of class 2(10) and 7％ of class 3(18). And then there was little difference in the rate of class distribution. 5. Through the above investigation, it was seemed that Japanese classification table was only prepared for the r∼w silk of Japan, considering that the width of class 1(4) in winding table was greatly tighter than that of Korea. Because it was generally evaluated that Korean silk in quality especially in the winding test was better (next to Japan) than any other countries. 6. We could venture to estimate that, applying to Japanese method, the testing result of break number in Korean silk would show from about 6 by Korean method to 9. And then it would be found degrading hi the testing result of winding test increased gradually.