The religious mysticism is a universal phenomenon which is prevalent with its specific practices in the different countries. The meaning of “Tao” cannot be expressed simply through the words as it draws parallel with the word “Muo” and that the etymology of the mysteries originated from the Greek language. The Tao Te Ching, a fundamental text of Taoism, asserts that ‘the Tao which can be trodden is not the enduring and inflexible Tao’ (道可道 非常道). There are vicious position and hidden truth of the word that cannot be articulated and explicated in words. The Tao mysticism has traversed and influenced the different religious practices across the world. Particularly, Buddhism had been accepted and practiced in many quarters of the world with Taoist mysticism. Taoism is one of the central traditional thoughts along with Confucianism in China, as well as in East Asian regions. Taoism is not a monotheist practice; rather it is a practice of polytheism where historically human beings have been the subjects of faith. As well as it emphasizes the subjects of faith by the embodiment of nature worship, and the worship of the Buddhist figures and Confucianism. It needs to mention that the Confucianism does not deal with the supernatural beings however, Buddhism does and it has assimilated various Taoist folklores during the course of history. If there was only Confucianism in China and not the Taoism, the propagation of Buddhism would have been quite hard. It is imperative to note that the Chinese people accommodated Buddhism in the matrix of the Taoist practices which were part of socio-religious practices of each social stratum. And the popular notion is termed Kyeak ui ( 格義, Buddhism paraphrase by Taoism) Buddhism.
When Buddhism was introduced and spread throughout China, the people were not capable to comprehend the Buddhist practices as it was a novel notion. Then the Chinese people started to employ the existing concepts of Taoism in order to understand the true meaning of Buddhism, Buddhist practices and the massage of the Shakyamuni Buddha. Evidently, the Buddhist sutras and chanting were predominantly inscribed in Sanskrit and Pali languages that were gradually translated into classical Chinese language. Moreover, the unfamiliarity with Indian words was a major hurdle in penetration of Buddhism to the main stream of society. Therefore, it was the Taoist practices and symbols that initially helped Buddhist scholars to explain the Buddhism to the Chinese scholars and masses.
The concept of Sunyata of Mahayana Buddhism was accepted as an Emptiness (無) of Taoism. Taoism extended a strong base and spiritual soil for the doctrinal acceptability of Buddhism in China. On the contrary, Taoism was also influenced by the Buddhist religious practices that brought in China.
The characteristics of Taoism are not clear because of its diversity and as it became conventional and assimilated various ideas of Laozi and Chuangzi, as well as the old folklores. The Taoist mysticism embedded with the idea of Taoist hermit which is a vision for immortality achievable through the training Taosim. And which is the dream of eternal life and youth and civic folklores. We need to outline that how the Taoist mysticism influenced the Buddhist ideas in China? First, Buddhism was interpreted as a philosophy of Taoist hermit, and gradually Chinese Buddhism was projected as a kind of Taoist hermit. Second, Buddhist’s breathing technique was interpreted as an idea of Naedan (internal alchemy), and particularly the Zen Buddhism shares the Taoism discipline. Finally, Chinese people interpreted Buddhism in order to invoke blessing from supernatural forces. Therefore, Chinese Buddhism engrossed the various supernatural folk beliefs, and made root to the East Asian countries including China.
Taoist Mysticism and Buddhism
The Taoist hermit never dies and people enjoy life forever. Taoism accommodated the ideas of hermit for longevity and they practiced breathing skill and produced distinct medicines. Ge Hong (283—343 C.E.) wrote Baopuzi (抱朴子. Master who Embraces Simplicity) that contains various subjects related with astrology, guidelines for hermits, and medicine manufacturing techniques and elixir for the life. According to the description, a Hermit is largely divided into two major fragments known as Ground Hermit and Heaven Hermit, and where their dream is to enter into Ground Hermit. The Ground Hermit needs special training in order to be part of it, and the practice are – first taken the Golden Medicine for elixir of life and next is to creating inner medicinal practices through regimen and breathing. Instead of focusing to make the Golden Medicine, they focus more importantly to train the inner Medicinal practices (internal alchemy) such as breathing and regimen. For Buddhism in China, it was necessary to become a Taoist Buddhism in order to communicate and develop harmony with Taoism. In the early Buddhism of China, the Buddha appeared to be a Taoist Hermit and a heavenly God who offers blessing and happiness to people. Moreover, the Chinese people were interested in Buddhism for sake of good luck and ward off calamities by Buddha’s blessing. The Emperor Hwan during the later period of Han Dynasty accepted Buddhism firstly, and treated the Buddha and Buddhist monks very analogous to the Laozi, emperor and Taoist monks. The Buddha became a subject of religious God having powerful abilities; and the Indian monks who came to China used the occult practices for the propagation of Buddhism. Therefore, it appears that Buddhism has accepted several beliefs and forms related to the temporal and utilitarian Taoism of the late Han Dynasty. Thus, Buddhism accommodated local Emperors, Laozi and old technology in order to gradually expand its force. In the early Buddhism of India, the Buddha did not profess himself a person with supernatural powers. The Buddha Shakyamuni succeeded through the self will power and truth. He never mentioned that people one should depend on God or supernatural beings. During the course time, these truths were difficult to come into existence without deep faith in the Buddha. Unlike the early Buddhism, the worship of Buddha’s statue was an historic process. As more and more Buddha appeared and became mystify in India, and further the Buddha was accepted as a mysterious Laozi in China. The Buddha of Mahayana Buddhism, unlike early Buddhism, is not just a truth and mortal existence in history, but the Amita Buddha that exists in past, present and future forever. This is the Ground Hermit young forever and never die, and the Heavenly Hermit is in the Buddhist paradise. Buddhism assimilated the Taoist thought and gradually and naturally became a potent religious force in the East Asia.
The Training of Taoist Internal Alchemy and Buddhism
1. Forgetting be seated and Zen in the Seating
For being Taoist hermit, the Taoist take special medicine called Outer alchemy, but later on they try to figure out alchemy in the human’s inner body. This is very similar to the Zen practices. The teaching of Taoism focuses to intact the mind and spirit and remove the desires and delusions. And finding the Emptiness and ‘Great Tao’ are the starting point of everything. Along with a Great Tao, one would return to the Tao, and one gain the Tao, and then he/she can exist forever. This is just how to perceive and get into the Inner Alchemy. The training of the Inner Alchemy was not imported from Buddhism, but it was already prevalent and discussed at Zhuangzi such as Sitting and Forgetting.
According to the canonical text, once “Yan Hui said that that ‘I am making progress,’ Zhongni replied, ‘What do you mean by making progress?’ And Hui replied, ‘I have ceased to think of benevolence and righteousness,’ ‘ Zhongni said very well; but that is not adequate.’ Another day, Hui again saw Zhongni and said; ‘I am making progress.’ The master replied ‘what do you mean?’ ‘I have lost all thought of ceremonies and music.’ ‘Very well, but that is not enough.’ A third day, Hui again saw (the Master) and said, ‘I am making progress.’ the master replied ‘what do you mean?’ ‘I sit and forget everything.’ Zhongni changed countenance and said, ‘what do you mean by saying that you sit and forget (everything)?’ Yan Hui replied, ‘my connection with the body and its parts is dissolved; my perceptive organs are discarded. Thus leaving my material form, and bidding farewell to my knowledge, I become one with the Great Pervader. This I call sitting and forgetting all things.’ Zhongni said, ‘Once (with that Pervader) you are free from all likings; so transformed, you are become impermanent. You have, indeed, become superior to me! I must ask myself to follow your footsteps.”
This conversation do not based on the Confucian text and accounts. And at this juncture the meaning of ‘Sit and Forget’ is not only to forget the benevolence and righteousness but also to forget oneself, and distinction between right and wrong. This explores the real insight that to be one with Great Tao and to be flexible. Sima Cheng Zhen (647-735) also wrote a treatise focusing on Sit and Forget (坐忘論), which is based on the accounts of Laozi and Chuangzi, and emphasizes to cultivate the spirit by maintaining tranquility.
This book introduces the idea of Tao by emphasizing the great tranquility from Reverence and Faith (敬信), Severing Connections (斷緣), Recollecting the Mind ( 收心), Simplifying Affairs (簡事), True Observation (眞 觀), Peaceful Stability (泰定), and Obtaining the zest of Tao(得道).
Furthermore, in the inner core of body, the Reverence and Faith (敬信) to be forgot, and also to forget the universe and world outside in order to become one with a great Tao, and where some senses are removed and attentions on state of mind. And have to belief that there is no Tao in addition to the mind.
Dissolving Connections (斷緣) are taken away with anguish and have to go through a simple and quiet life with the heart, and worldly action has gone farther close to the Tao. Recollecting the Mind (收心) means sitting comfortably and concentrating on the mind, and further to abandon the subjects and stay in non-possession. Simplifying Affairs (簡事) means to make and rationalize work where knowing one’s attitude doesn’t matter, and being away from the wealth, vigorous and delicious food, fabulous clothes, and social honor. True Observation (眞觀) means the body and spirit become calm and free and perceive the subject rationally. Through these practices one finds great comfort and reaches to the Tao. It needs to note that the similar Taoistic method is described in Zen Buddhism.
2. Inner Elixir and Breathing
The breathing is divided into two parts breathout and breath-in. In the form of human embryos one receives oxygen through the placenta, and the process of breathing starts after being out from the womb. Needless to mention that the life depends on breathing and stoppage of breathing means death. The breathing through placenta or hypogastric breathing in Taoism, in fact is a natural regimen. Chuangzi mentions about the breathing concept of Taoistic hermit, and according to him following is the story of the breathing:
“The true men in their old-age did not contemplate when they slept, and had no anxiety when they awoke, and did not care that the food should be delicious. Their breathing came deep and silently. The breathing of the true man comes (even) from his bottom, while ordinary people breathe only from their throats.” 
Inner Elixir practice and abdominal breathing is very similar to the Zen practices. The‘Danjean (the lower abdomen) carries vitality between the belly and kidney. The Danjean is a fundamental power house of human beings where mental and the source of five vitalities lies. Man places their sperm there and woman conceives and bears child by stopping the menstruation course and it is the gateway of entry and a joint place of Yin and Yang.’
The purpose of the Taoist breath is contemplation, a means to perfect the mind. Remove all kinds of thoughts from the mind for creating inner emptiness, and then will be conceivable to meet with true self. The process of slower breathing with the abdomen keeps the mind calmly. In order to achieve the level of ultimate stage one needs slightly progressive training. Above mentioned the Sit and Forget process is a training method to accomplish the ultimate stage, and the non-action remove the images of self and other. 
The discipline in Taoist Waibaiyang (魏伯陽) is the skillfulness to maintain harmony between Yin and Yang, it is like putting the kidney’s water energy and downing the heart’s fire energy for upholding stable body. He understands ‘the book of Change’ as a principle of the universe and also saw the principles of human’s regimen. The point is to maintain both physical and mental health through the balance of Yin and Yang and like a Taoist hermit for long-life.
When Indian Buddhism was introduced to China, it already brought a sophisticated practice of breathing. Buddhist breathing practice is also one of the important methods of practicing meditation and to remove distracting thoughts, which has been existed from the Buddha’s time and ultimately leads to the enlightenment. Zen Buddhism in China highlighted practice of Zen meditation, whose sitting and breathing practice is very similar to the inner elixir practice prevailing in Taoism.
3. Lao-Chuang Philosophy and Zen
There are parallels between Zen Buddhism and Lao- Chuang. Moreover the Zen basically corresponds with a Lao-Chuang philosophy. Zen and Lao-Chuang argue about the distraction from the real world. How can one achieve nirvana by escaping reality? Laozi states that he/ she should not be meddling with outer objects. Chuangzl argued about the beyond self, outer objects, right and wrong, and to maintain the stillness and emptiness in life.
How about Zen practices? The Zen practices adopted and developed the Laozi and Chuangzi’s idea and further suggested for a complete freedom from all ideas. And remain pure, undefiled heart and away from all the anguish by doing so. Kōan Zen is also related to the traditional Taoist idea that originated from wholesome conversation during the Six Dynasty (220–589) China. Zen talk was not originated from the Indian’s Dharma meditation. Nevertheless, Zen talking had been formed in the pure talking originated from Taoism. It is imperative to note that the Pure Talking is not bound by any secular resonance and beyond the manners and morals and freely enjoy the nature.
The tangible discourse of their tradition cannot be understood through the common sense, and it need to be deployed as a Zen riddle. The discourse is not in a worldly sense for a long time, and the tradition was inherited to Zen riddle. During the 2nd and 4th century, the Taoist monks and Buddhist monks usually enjoyed adjacent association. The Taoist teachers were well known to the Buddhist scriptures and the Buddhist monks also understand the Taoism. There was a mutual understanding and exchange between these two tradition and their practices. The Zen practice emerged as a denomination of Buddhism but it combined subtle and sophisticated philosophy of both traditions Buddhism and Taoism.