The Mozhen Well complex is elevated from a height. According to Wudang Taoism, when the sun rises every day, it is the first place to receive pure Yang energy, so it is also called the "Pure Yang Palace". The Grinding Needle Well is a typical small-scale building in the ancient architectural complex of Wudang. It is compactly arranged and dainty. The main structure of the building is based on the story of Zhenwu's cultivation on Wudang Mountain.

It is said that Zhenwu was the crown prince of Jingle Kingdom and entered Wudang Mountain to practice Taoism at the age of fifteen. After decades of practicing the Great Way in the deep mountains and old forests but failing to achieve it, he became disheartened and decided to abandon the Tao and return to the mundane world. Here, he met the Purple Qi Yuan Jun who had transformed into an old woman and used an iron rod ground into a needle to enlighten him, enabling him to understand the truth that "an iron rod ground into a needle will naturally succeed with practice." Thus, he returned to the deep mountains to continue his cultivation.

On the gable wall inside the main hall of the Grinding Needle Well, there are still murals depicting the true martial arts cultivation. The mural, with its delicate and vivid brushstrokes, vividly depicts the entire process of the legendary Zhenwu from his birth to his cultivation in the mountains and his attainment of enlightenment. The beautiful legend of "Grinding an iron rod into a needle" has been endowed with lasting vitality due to its profound philosophy. For thousands of years, it has been widely praised and has become a unique branch of Wudang culture.

The Mozhen Well was built during the Qing Dynasty. According to the inscription "Record of the Construction of the Pure Yang Palace on the Mozhen Well in Taihe Mountain" written by Dang Juyi, the governor of Junzhou in the 12th year of the Kangxi reign, we learn that in the early years of the Kangxi reign, Li Changzhu, the master of the Old Mu Pavilion, informed the governor and other officials that there was an incident of "being enlightened by Lu Zu in a night dream". Therefore, Governor Du Yangxing and others jointly funded the construction of the Pure Yang Palace here.