Orthodox Collected Taoist Scriptures • Cavity God Volume (Zheng Tong Dao Zang Dong Shen Bu) written in the Ming Dynasty said, "The SI Exercise is related to the lungs, which connect the internal organs”. People usually have a stuffy nose when catching cold and the SI Exercise is a good way to treat the diseases. “It has pointed out that the SI Exercise can discharge the foul smell of the lungs and regulate the functions of the lungs. The SI Exercise exactly corresponds to the lungs. The expiration and inspiration, as well as the body movements of the SI Exercise are mainly designed for the lungs.

The lungs: the (heart’s) assistant officer with similar functions to the prime minister

According to the different functions of the five internal organs, the traditional Chinese science of health preservation compares the heart to the monarch and the lungs to the assistant to the monarch, which plays the roles of the prime minister, so the lungs are also called "the (heart’s) assistant officer with similar functions to the prime minister". The main functions and features of the lungs are introduced as below.

First, the lungs govern qi and control the respiration. As we mention the lungs, the first thing we think of is their respiratory function. Respiration (breathing) is indeed the main function of the lungs. Controlling the respiration mainly means that the lungs are responsible for breathing as a vital movement. The opening and closing of the lungs are expressed outwardly as the inhalation and exhalation, respectively. The main content of breathing is the air (qi) between heaven and earth, for this reason, it is said that the lungs govern qi. The lungs governing qi mainly means that the lungs, as the place for gas exchange, control the qi inhaled and exhaled. Through the respiration function of the lungs, the stale is exhaled and the fresh is inhaled, in order to achieve gas exchange between human viscera and the outside world, so as to maintain the life activities of human body. It is just as Plain Questions • On Principles of Yin and Yang (Su Wen • Yin Yang Ying Xiang Da Lun) said, "The nature and the qi communicate with each other through the lungs".

Second, all vessels converge in lungs and the lungs are responsible for governance and regulation. What is the relationship between the lungs and all vessels? Why do we say that all vessels converge in the lungs? The main reason lies in that, when the blood from all parts of the body flow into the lungs through numerous vessels, clear qi and turbid qi are exchanged by the respiratory function of the lungs, whereby the blood with clear qi is transported to all parts of the body through numerous vessels, while the turbid qi in the blood is excreted from the body by the respiratory function. The gas exchange process in the lungs is very much similar to the scenario of many ministers presenting themselves before the monarch, so it is called “all vessels converging in lungs”.

Furthermore, the heart governs the blood vessels of the whole body, and it is also the fundamental driving force for blood circulation. However, the promotion and regulation of lung qi is joined in the blood circulation through the process of “all vessels converging in lungs”, which plays a significant supporting role for blood circulation of the heart, so ancient people called the lungs as "the (heart’s) assistant officer with similar functions to the prime minister". The lungs are responsible for governance and regulation, which mainly means that the lungs function to control the respiration and regulate the blood, qi and water in the whole body. Governance here means management, while regulation here means adjustment. Plain Questions • The Secret Treatise of the Spiritual Orchid (Su Wen • Ling Lan Mi Dian Lun) said, "The lungs are the (heart’s) assistant officer with similar functions to the prime minister, and they are responsible for governance and regulation." The lungs’ function of governance and regulation is mainly reflected in four aspects, including: governing the respiratory movements, regulating the ascending and descending of qi movement, adjusting the operation of the blood, and regulating the metabolism of body fluids. For these reasons, the lungs’ responsibilities for governance and regulation highly summarize the main physiological functions of the lungs.

In addition, the traditional health science also believes that the lungs are the canopy of the internal organs and they keep the normal flow of body fluids. The term "canopy" mainly refers to the location of the lungs. The lungs are at the highest place, covering other viscera, which are just like the canopy. The lungs keeping the normal flow of body fluids mainly means that the ascending and descending of the lung qi can promote and regulate the transportation and excretion of the body fluids. It is just as Plain Questions• On Channels (Su Wen? Jing Mai Bie Lun) said, "Dredging and regulating the fluid passage". The lungs keeping the normal flow of body fluids mainly include two aspects, namely dispersing upward and outward, as well as purifying and descending downward and inward. First, dispersing upward and outward mostly means that the clear fluids and essential substance from foodstuff from the spleen are transported upward and outward by the lungs to the head and skin of the whole body. The fluids are transformed into sweat in this process, which are discharged out of the body under the regulation of the defensive qi. Secondly, purifying and descending downward and inward mostly means that the thick fluids and essential substance from foodstuff from the spleen are transported downward and inward by the lungs, in order to moisten and nourish other internal organs. The turbid fluids generated in the metabolism of internal organs are transported downward to the kidneys, becoming the source of urine. Collection of Prescriptions with Notes (Yi Fang Jie Ji) written by Wang Ang in the Qing Dynasty said, "The lungs are the upper source of water". It has vividly and precisely describes the function of the lungs in the disturbance of water metabolism.

The sound of "Si" should be the dental sound in the SI Exercise. The pronunciation method is that aligning the upper and lower front teeth, with the tongue gently supporting the inside of the lower front teeth. Dental sound refers to the sound that the pronunciation focus is in the vicinity of the front teeth. In order to achieve accurate pronunciation, the positions of the teeth, tongue and lips need to be adjusted. First, adjust the positions of the teeth. Align the upper and lower front teeth in the practice of pronunciation. The mouth is naturally closed when aligning the upper and lower front teeth, so the air flow can only rush out through the gaps between the teeth in the pronunciation. It should be noted that the mouth can not be open, all the teeth are closed, and the upper and lower front teeth need to gently connect. Pay attention to experience the focal point near the front teeth in the pronunciation, which is the key to make the dental sound. Second, adjust the position of the tongue. The tip of the tongue should gently touch the inside of the lower teeth in the pronunciation. It also aims to lead the pronunciation focus toward the front teeth, so as to make the accurate dental sound. In the process of pronunciation, the tongue unfolds naturally and easily in the mouth, and the tip of the tongue moves slightly forward, touching the inside of the teeth. Besides, pay attention to the positions of the lips. There are not special requirements on the positions of lips in the SI Exercise, but according to some issues appeared in the practice process, it needs further explanations here. In the pronunciation, the mouth and lips open normally without force, oral of avoid by all means. If the mouth and lips open excessively with force, it will directly affect the pronunciation focal point, so as to the accurate dental sound can not achieve. In order to achieve the accurate pronunciation, we can summarize the formulas as follows. Align the incisors and close the mouth, put the tongue against the inside of teeth and relax the lips.

The dental sound can regulate the lungs and purge the turbid qi in the lungs. From the view of the five elements, SI Exercise corresponds to the lungs. The dental sound matches the metal, so do the lungs. Thus, only the accurate dental sound in the SI Exercise can correspond to the lungs. The metal in the five elements is characterized by convergence, settlement and stabilization. The lungs play the roles of breathing, exchange of substance, dispersing and descending of the Qi movements, which are similar to the metal, so it matches the metal. In the pronunciation of the dental sound, the airflow can rush out from the teeth, which is like the sound of the stone and gold, so it matches the metal in the five elements. Viewed from the hard nature of the dental sound, SI Exercise contributes to complete the functions of dispersing and descending, as well as ascending and descending of the lungs. The pronunciation focus in the SI Exercise is between the teeth, the airflow is obstructed in the teeth and get the crisp and long sound, which likes the sound of stone and metal, forming the frequency conforming to the activities of the lungs, so as to adjust the lung qi.

The body movements of the SI Exercise can regulate the lungs. The body movements of the SI Exercise mainly include that draw palms back to the Zhongfu acupoint, open the shoulders and stretch the chest, shrink the head and neck, pronounce the word and push palms. It contains the theory of regulating the lungs in the whole process. First, draw palms back to the Zhongfu acupoint. The Zhongfu acupoint is the starting point of the lung channel, and Shaoshang acupoint in the inside of the finger points of the thumbs are the end of the lung channel. Drawing the thumbs of the palms to the Zhongfu acupoint can connect the Shaoshang acupoint and Zhongfu acupoint, so the lung meridian of hand-taiyin is end to end. In the process of drawing the palms, palms are opposite, drawing in the, which aim to make the Shaoshang acupoint in the finger points of the thumbs exactly correspond to the Zhongfu acupoint. Second, open the shoulders and stretch the chest. They all aim to expand the chest, enlarge the capacity of the chest, and inhale the clear qi as much as possible. As mentioned above, the lungs govern qi and control the respiration, and this action is just designed to complete the functions of the lungs at the most extent, taking a deep breathing and absorbing qi as much as possible. It should be noted that opening the shoulders and stretching the chest should be completed at one stretch, which means that the two actions should be completed in the process of inspiration. Try not to take a breath in the middle, or the effects of taking a deep breathing and absorbing qi can not be reached. Third, pronounce the word and push palms. Before pronouncing the word, relax the shoulder and close the chest, straighten the head and relax the neck. The Shaoshang acupoint of the thumbs leave away the Zhongfu acupoint, while pronouncing the word. Opening the shoulders and stretching the chest, as well as shrinking the head and neck aim to absorb qi widely, while pronouncing the word and pushing palms aim to make air out. Absorbing qi and making air out as much as possible can fully improve the respiratory function of the lungs. Push the palms forward simultaneously, the Shaoshang acupoints are opposite to each other, so the two lung channels at the right and left side of the body are opposite to each other. The two lung channels of the body are exercised in the process of pronouncing the word and pushing palms. We can summarize the movements formulas as follows, namely relax the shoulders and neck, and straighten the head, both Shaoshang acupoints forward are opposite, while pronouncing the word Si.

The formulas of the methods in the SI Exercise

Align the incisors and close the mouth, put the tongue against the inside of teeth and relax the lips. Relax the shoulders and neck, as well as straighten the head, both Shaoshang acupoints forward are opposite, while pronouncing the word Si.

（By Chao Shengjie）