The early Buddhist schools in China were each based on a specific sutra. At the beginning of the Tang Dynasty , by the time of the Fifth Patriarch Hongren (601–674), the Zen school became established as a separate school of Buddhism.  It had to develop a doctrinal tradition of its own to ascertain its position,  and to ground its teachings in a specific sutra. Various sutras were used for this, even before the time of Hongren: the Śrīmālādevī Sūtra ( Huike ),  Awakening of Faith ( Daoxin ),  the Lankavatara Sutra (East Mountain School),   the Diamond Sutra  ( Shenhui ),  the Platform Sutra .   None of these sutras was decisive though, since the school drew inspiration from a variety of sources.  Subsequently, the Zen tradition produced a rich corpus of written literature which has become a part of its practice and teaching. Other influential sutras are the Vimalakirti Sutra ,    Avatamsaka Sutra ,  the Shurangama Sutra ,  and the Mahaparinirvana Sutra . 
The path to so-called enlightenment is not paved with Zen riddles or notions of the mystical. It is paved with unbending intent and the extreme desire to find one’s own spirit self buried beneath the indoctrinated illusions of the ego and its limited perceptions of the world. When one is ready to move past ego intellectualizing and transcend into spiritual knowing, then they will get there. All the mystical riddles in the universe will not lead anyone one step closer to understanding enlightenment. Such riddles are simply a distraction for the ego to avoid one finding themselves without their ego as lord over their consciousness. Beat the ego and the true self comes forth. This is enlightenment – to be aware of the spirit consciousness within. It is not eternal joy, happiness and docility; it is strength, power and spiritual self-reliance.