“SILK SOCKS TO FIGHT THE COLD” People in Okayama Prefecture have traditionally kept their feet warm by Hietori, layered socks, to fight the cold. Kurabiz introduces four layers of silk and wool socks to lock the heat and warm your feet. The heat locked into your feet will extend upwards to warm your lower body. We wish you plenty of warmth, smiles and Hietori comfort. Kurabiz specializes in four sets of 100% wool and 100% silk socks called Kurashikinu, to keep you warm. Since it is believed that poor blood circulation due to cold causes many types of illnesses, putting on four layers of socks heats your lower body, and will also improve your immune system.