631–655), courtesy name Zishi (子實), was a Taoist monk known to posterity as the "Master of Doctrines at Xihua Abbey“ (西華法師) and was one of the principal representatives of the "School of Double Mystery" (Chongxuan) during the reigns of the emperors Taizong and Gaozong of the Tang dynasty.
He lived in Donghai in seclusion until 631, when he was summoned to the Tang capital Chang'an and appointed the head monk of Xihua Abbey by the imperial decree of Emperor Taizong.
[4] In 636 and 638 Cheng was present for a series of debates between Daoists and Buddhists at the temple of the monk Huijing (慧凈 b.578) along with Cai Zihuang (蔡子晃), a fellow Chongxuan adherent.
[12] Cheng believed that the Dao "is eternally deep and still, it is neither form nor sound, neither personal name nor style; solitary, it alone surpasses the logic of the tetralemma, vague and indistinct it goes beyond the hundred negations.”[13] Cheng's commentary on the Lingbao Scripture of Universal Salvation, the Clarified Meaning of the Scripture of Universal Salvation (度人經疏義), was extremely popular in its time and likely resulted in his summoning to Chang'an in 631.
Additionally, Cheng composed a work in 5 juan on the Classic of Changes, the Diagram on the Circulation and Development of the Changes of Zhou (周易流演窮寂圖), which is lost and rarely-mentioned.
Records of the work say it "examined across and synthesized all sixty-four hexagrams and explained the Nine Palaces, extrapolating the weal and woe of the state down to the months and days.