Liang Lingzan was a Tang Dynasty

Tang Dynasty

The Tang Dynasty was an imperial dynasty of China preceded by the Sui Dynasty and followed by the Five Dynasties and Ten Kingdoms Period. It was founded by the Li family, who seized power during the decline and collapse of the Sui Empire...

 military engineer and government official of the Kaiyuan era. He invented a mechanized water clock with the Tantric

Vajrayana

Vajrayāna Buddhism is also known as Tantric Buddhism, Tantrayāna, Mantrayāna, Secret Mantra, Esoteric Buddhism and the Diamond Vehicle...

 monk and mathematician Yi Xing

Yi Xing

Yi Xing , born Zhang Sui , was a Chinese astronomer, mathematician, mechanical engineer,and Buddhist monk of the Tang Dynasty...

 . It was actually an astronomical instrument that served as a clock, made of bronze

Bronze

Bronze is a metal alloy consisting primarily of copper, usually with tin as the main additive. It is hard and brittle, and it was particularly significant in antiquity, so much so that the Bronze Age was named after the metal...

 in the capital of Chang'an

Chang'an

Chang'an is an ancient capital of more than ten dynasties in Chinese history, today known as Xi'an. Chang'an literally means "Perpetual Peace" in Classical Chinese. During the short-lived Xin Dynasty, the city was renamed "Constant Peace" ; yet after its fall in AD 23, the old name was restored...

 in the 720s. It was described by a contemporary text this way:

[It] was made in the image of the round heavens and on it were shown the lunar mansions in their order, the equator and the degrees of the heavenly circumference. Water, flowing into scoops, turned a wheel automatically, rotating it one complete revolution in one day and night. Besides this, there were two rings fitted around the celestial sphere outside, having the sun and moon threaded on them, and these were made to move in circling orbit ... And they made a wooden casing the surface of which represented the horizon, since the instrument was half sunk in it. It permitted the exact determinations of the time of dawns and dusks, full and new moons, tarrying and hurrying. Moreover, there were two wooden jacks standing on the horizon surface, having one a bell and the other a drum in front of it, the bell being struck automatically to indicate the hours, and the drum being beaten automatically to indicate the quarters. All these motions were brought about by machinery within the casing, each depending on wheels and shafts, hooks, pins and interlocking rods, stopping devices and locks checking mutually.

In addition to being an engineer and official, Lingzan was also a scholar and artist. He wrote The Five-Planet and Twenty-eight Constellation Deities , of which a Song Dynasty

Song Dynasty

The Song Dynasty was a ruling dynasty in China between 960 and 1279; it succeeded the Five Dynasties and Ten Kingdoms Period, and was followed by the Yuan Dynasty. It was the first government in world history to issue banknotes or paper money, and the first Chinese government to establish a...

 copy resides in the collection of the Osaka City Art Museum.