Sacred Daoist Mountain of Eastern China
Mao-shan [茅山, Grass/Reeds Mountain] was one of the great and famous sacred mountains of
traditional China, located near
Nanjing City, in Jurong County [句容市] of Jiangsu Province [江苏省].
It was and remains the principal seat of the
Shangqing [上清, Supreme/Highest Clarity, or Primordial
Purity] School of classical Daoism.  It's original name is said to have been Juqu-shan (句曲山).

Wei Huacun (251-334) is regarded as the founder of the Shangqing School, but
Tao Hong-jing
(456-536?) who compiled its scriptural canon and systemitized its theory and practice is
more usually considered to be its true founder, and his reputation as a spiritual master greatly
contributed to the rapid development of the school that took place around 500 CE and afterwards.  
He established his primary retreat and school-temple named Huayang-guan [Flourishing Yang Hall]
at Mao-shan in 492.  By the mid-500s and on into the 600s it flourished as a large and very diverse
religious community close to the important cities  Kaifeng and Nanjing.  It hosted major festivals, and
its many temples and shrines were filled with both renunciate and married monks, and with pilgrims,
scholars, artists, devotional practitioners, hermit-meditators, retired/vacationing officials, and more.

Classical Shangqing practice mainly involved breathing-visualization meditation techniques that
upgraded circulation of
Qi  [氣, ch'i, vital energies; gi in Korean] within the adept's body-mind, as
well as some energy-moving physical exercises (similar to Tai Chi Chuan), as opposed to the
superstitious use of divination, alchemy and talismans -- and recitation of the sacred scriptures
also played an important role.   They taught that Qi is a delicate flowing stream that, once it is
mastered by inner-alchemy meditation, can be "ridden" into & out-of human and other natural
forms as a way of practicing "immortality".

These practices were essentially individualistic, contrary to the collective-ritual practices of the
Celestial Master and Lingbao Schools.  During the Tang Dynasty Shangqing was the dominant sect
of Daoism, recruiting many monks and lay-followers from high social classes, and its influence is found
in the literature of that era.  Its importance then began to diminish beginning from the second half of
the Song Dynasty.  During the Yuan and Ming, the diminished movement was known by the name
"Maoshan Sect" and the focus steadily degenerated from meditation practice to rituals and talismans.
During the 19th and 20th centuries, the worst long era in all China's history, the combination of the
Taiping Rebellion, the WW-II Japanese Invasion and the radical-communist Cultural Revolution
completely destroyed all of the temples on Mao-shan, a historic tragedy of cultural heritage sites.  
The Beijing regime puts most of the blame on Imperial Japan, claiming that its intensive bombing
during the seige of Nanjing destroyed hundreds of buildings and killed 15,000 people.

Two of the ancient temples, Jiuxiao-gong and Yuanfu-gong, have been rebuilt by modern local
governments, but only for tourism and not for any authentic religious or spiritual-practice purposes.
The Laozi-Jinshan Temple, with a gigantic statue of Laozi the legendary founder of Daoism, has
been added at Qixia-shan near Mao-shan as a modern tourist attraction.   Along with the Beijing
regime's general crackdown on religions (with renewed persecution-vigor in the early 2010s), only
government agents dressed in monastic robes and faking the rituals in order to collect donations
operate those shrines.  There are some people inside and outside China who are claiming to
practice and teach Shangquing/Maoshan Daoism, but their doctrines and techniques are extremely
different from the original ones that developed and flourished in the Tang Dynasty.
A temple now rebuilt on Mao-shan
The Laozi-Jinshan Temple at Qixia-shan near Mao-shan and Nanjing City