Origin：One theory is that it originated from the Jin Dynasty in China. In ancient China, the emperor had many wives and concubines and had absolute power, and the custom at that time was that the emperor rode in an oxcart every night to the residence of his wives and concubines, and stayed there wherever the oxcart stopped. In order to make the oxcart stop, some people put the ox's favorite salt piled up in front of their house (salt was very expensive at that time) encounter salt, the ox stopped to lick the oxcart did not move the emperor said, tonight in this.

The legend spread to Japan, and later it was spread as a sign of good luck, and now it is still practiced in ryokan, restaurants, and other places. Two small piles of salt are piled up on either side of the cleaned doorway.