As the heel is at a right angle, the socks are knitted at a right angle to wrap comfortably around the heel and prevent the fabric from sagging and slipping off. Smooth textured pile on the sole. Size Chart Japan (cm) US (Women's) US (Men's) 21-23 5-7 3-5 23-25 7-9 5-7.5 25-27 9-11 7.5-10 27-29 11-12.5 9-11 29-31 13-15 11-13