In ancient times, in the west of Xiaofangcheng, Gansu Province, there was a post station called "Horse Lost Rabbit", also called "Horse Lost Rabbit". Caravans must pass through here to transport jade from the border to the Central Plains. The terrain here is very complicated: swamps are everywhere, ravines are criss-crossing, forests cover the sun, and weeds are everywhere. Whenever caravans carrying jade catch up with the hot weather, they always like to travel in the cool at night in order to avoid heatstroke of people and animals during the day. So whenever cavalry comes here, it is always dark and can't tell the direction. Even the old horses who often travel back and forth on this road will be confused and difficult to find their way. That's how the name "lost horse" came from.

There is a caravan selling jade and silk. It travels along this road all the year round and often gets lost in the "lost horse" Once the caravan got lost as soon as it entered the lost horse. People were very anxious, and suddenly a lone goose landed not far away. A young man in the caravan quietly caught the wild goose. He is kind-hearted and holds it in his arms, ready to take it out of the "lost horse" and then let it go.

After a while, I saw the wild goose purring at the young man with tears: "Gollum, give me food, I'm going to get lost." After listening to this, the young man suddenly realized that the geese were left behind because they were too hungry to fly, so he immediately took out his own dry food and water to feed the geese. After eating and drinking enough, the geese flew into the sky and kept circling, leading the caravan out of the "lost horse" and reaching the destination Xiaofang City smoothly.

After a while, the caravan got lost in the "lost horse", and the wild goose flew in the air and cried, "Gollum, the caravan is lost. Gollum, the square plate is inlaid with jade. " They called and flew, leading the caravan astray. Only the young man of the wild goose understood what the wild goose said and told the leader's boss, "The wild goose told us to put a luminous dark green jade in the small square city. After the caravan has a goal, it will never get lost again. " Hearing this, the boss felt that a piece of luminous dark green jade was worth thousands of taels of silver, and he could not bear to part with it, so he did not agree.

Unexpectedly, the next time the caravan got lost in the "lost horse", it could not find water for several days. The camel was panting with thirst, and everyone was thirsty, and their lives were at stake. Just then, the wild goose flew again and cried in the air, "The caravan is lost, and the square plate is inlaid with jade." Never leave Mo Yu and never lead the way. " Hearing this, the young man quickly told the boss. The boss panicked and asked the young man what to do. The young man said, "You should kneel down and swear to the goose:' You must be inlaid with jade and never break your word.' "

The boss immediately swore to the kneeling geese as the young man said. When the geese heard this, they spun in the air for a while, which led to the caravan's "lost horse" being saved again. After arriving in Xiaofangcheng, the boss never dared to love money again. He immediately picked out the biggest and best glowing dark green jade and put it on the top of the building. Whenever night falls, this jade shines brightly and can be clearly seen dozens of miles away in Fiona Fang. Caravans used to have goals and won't get lost again. Since then, Xiaofangcheng has been renamed "Yumenguan". In fact, Yumenguan was built by Emperor Wu of the Han Dynasty, because it was an important traffic artery leading to the western regions in ancient China. Hetian jade stone was imported from the western regions and entered the customs from then on, hence the name.