According to the legend, the Ming Dynasty steered a new defense policy to resist the enemy of the northwest. The new policy included the construction of Jiayu Pass. The supervisor Hao Kong, the project director, was cruel and always beat craftsmen for nothing.

Among the craftsmen, there was a master called Yi Kaizhan. With superb skills, structured design, all the architectures he made are beautiful in appearance and very strong inside. He was famous for his skill of saving money on materials costs while still offering a high quality. Before the construction, in a domineering manner, Hao Kong asked Yi Kaizhan, “How many bricks do you need to build the pass?” “We need 999,999 bricks in total.” Yi answered with confidence. “I will give you bricks on the whole amount, but if you use more or less than 999,999 bricks to finish this Pass, even just one brick, I will chop off your head and force all the craftsmen into slave labor for 3 years.”

Fearless, Yi led the craftsmen to step up construction. After hundreds of days and nights of hard work, the Pass was finally completed, and all the craftsmen were very excited. Unexpectedly, a craftsman came to Yi Kaizhan with a brick. An extra brick! Just at that moment, Hao Kong came over and shouted at Yi, “You are wrong about the number! There is an extra brick! I will chop off your head tomorrow!”. “No. This brick is ‘Dingcheng Brick’. The pass would collapse if you moved the brick away!” Yi said in a relaxed tone. Hao Kong had nothing to say and slipped away.

As a memorial of the craftsmen’s contribution, the “Dingcheng Brick” was put on the rear eaves of Xiwengcheng Attic.