There is a folk saying. It is said that Li Shimin, the king of the Tang Dynasty, once lost the battle and ran. There was a muddy river in front of him, and the enemy troops wanted to catch up behind him. On the banks of the Ma Le River in Li Shimin, watching his beaten army, he couldn't help sighing: "I have been a soldier in Li Shimin all my life and fought many wars. Am I cornered today? " If the life of the emperor of the Tang Dynasty should not be doomed, I hope that God will have mercy and help me through this difficulty. I will never forget his kindness in the future! "The words sound just fell and Li Shimin saw thousands of crabs coming from all directions. These crabs crossed the river and built a crab bridge. Li Shimin was overjoyed when he saw this, and led the troops to cross the river in crabs. Looking back, Li Shimin saw enemy soldiers and horses approaching the shore. Li Shimin is afraid that enemy soldiers will also set foot on the crab bridge. He quickly shouted: "crab, crab, spread out quickly!" "Because they were stepped into the mud, one by one, they couldn't turn around for a while. Li Shimin shouted again: "You can climb sideways!" In this way, with the development of the training course, a crab bridge disappeared instantly, and the enemy soldiers could not catch up with Li Shimin, so they had to take the horse back.

Li Shimin, the emperor of the Tang Dynasty, who had the power of "talking with words", had a great deterrent effect on crabs. Since it was called "crawling sideways", I never dared to walk straight again, and it still is. Of course, the horseshoe prints on the crab cover were naturally printed by the military forces of the Tang Dynasty.