There is a pattern of "sea water" or "river water" in the bottom of the Picture of Inner Scripture, and the metaphor of the water is the filled kidney essence, which is also called Kanshui. The right side of the pattern of "sea water" or "river water" is marked with words of "Kanshui counterflow," in which the "Kanshui” refers to the kidney essence. How does the “counterflow” of kidney essence come into being? As the saying goes, "the filled kidney essence will overflow". Once the kidney essence is adequate, it is easy to outflow. However, by practicing to enhance a good fitness base, the health experts have completed the engineering of deficiency supplement, with adequate kidney essence and healthy body. How to "keeping the essence from discharging"? It is necessary to practice the routine, that is inhaling, touching palate, lifting anus, leading the essence by mind from the perineum to coccyx, passing Jiaji and Yuzhen into Niwan, and then holding the breath, dropping to the philtrum through the palate, exhaling and dropping down the tongue, leading the essence by mind from the Chonglou, Jianggong, down into the pubic region. It is clear that there are three passes in the “counterflow” of kidney essence.
The first pass is the coccyx pass. The coccyx is at the bottom of the tailbone, where locates the Zhangqiang acupoint, namely the first acupoint of Du Channel. It is the first pass of the “Kanshui counterflow”.
How does the kidney essence burst through this pass? In fact, as long as the Huiyin acupoint opens, the vital essence of pubic region can not ascend but down along the Du Channel naturally to the coccyx. Then as long as the tongue touching the palate, lifting anus and inhaling gently, leading the essence by mind will make it easy to burst through this pass and going up. The stream in the Picture of Inner Scripture is the metaphor of the entire spine, which is the channel of "Kanshui counterflow" and the road of ascending. Two of the three passes of Du Channel locate on the two ends of the spine, the coccyx pass is at the bottom, the Yuzhen pass is at the top and the Jiaji pass is in the middle.
The second pass is the middle Jiaji pass. The middle Jiaji pass is also named the Jiaji pass or rumble pass, which is the "Shendao acupoint” (equivalent to the dent under the fifth spinous process of thoracic vertebra in the modern anatomy) of Du Channel. It is located in the middle of the back and opposite to the heart and the middle pubic region in front. Jiaji pass is called the "Shendao acupoint”, the reason of which is because that it is the channel for the ascending of blood and qi, and also it is the vision, hearing, taste and the sixth sense.
The third pass is the upper Yuzhen pass. The upper Yuzhen pass is also named Yuzhen pass, which is the Fengfu acupoint of Du Channel. Located under the occiput. Yuzhen pass is the most important pass in the three passes of Du Channel and the pass, which is the most difficult to burst through. If the essence and qi circulating in the meridian is likened to a person, then the ultimate purpose of the person is to get the palace of a higher level after the three passes of practice, so as to keep the health of body and mind.
Then, is there any skills to burst through the pass? It goes back to the health wisdom revealed in "Picture of Inner Scripture", namely the sheep cart, deer cart and ox cart. The ancients called it the method of "three-cart moving".
Method 1: bursting through the coccyx pass by the sheep cart. Bursting through the coccyx pass requires a long-term practice of turning the coccyx, which is not easy for normal persons. The essence and qi burst through the coccyx slowly, so the ancients made it likened to the sheep cart, which is very gentle and slow like the sheep cart. Another feature of the sheep is endurance, and it is determined with a strong willing.
Method 2: bursting through the Jiaji pass by the deer cart. When bursting through the Jiaji pass, it should gallop as agile and rapid as the deer cart.
Method 3:bursting through the Yuzhen pass by the ox cart. This pass is very hard to burst through, which requires great efforts. It should exert to dash as brave as the ox cart. The viewpoints of the traditional Tao yin and life nourishing respected by the health experts all attached great importance to the so-called Ren Channel and Du Channel, which were also known as opening the three passes (the coccyx, Jiaji, Yuzhen).
（By Ou Liangshu）