The core or basics of Baguazhang's Circle Walking stem from older Daoist exercises/ Daoyin (Guiding and Leading), and then around that core the Martial Strengthening and Skill Training were added so that the practice 'Kills two birds with one stone'.
This basic function is to tuck under one's tailbone/ sacrum (roll the buttocks under); press or round out the back of the waist or lumbar part of the spine (yaobei); concave/ hollow the chest to relax the pericardium; but also expand or pull out the back part of your ribcage so the lungs are still given room to inhale, (essentially breathing into your back, instead of puffing up the chest); bring the crown of your head (Baihui point) to the uppermost top by lengthening the vertebrae of your neck and tucking your chin. And then hold these postural requirements as you walk around a point in the center and follow about a 6 foot (2 meter) diameter circle. Which will open and close the 'kua' (both hips). When the inside leg and hip move forward the 'kua' is opening; when the outside leg and hip move forward the 'kua' is closing. This rhythmic stepping/ opening & closing will squeeze and put pressure on one's sacrum, and will, with many total days and hours of practice, and over the course of time in each daily session, begin to move the Cerebrospinal fluid (CSF).
In Daoist terminology this is 'Surging water (marrow) upward', or sending 'Shen' (spirit) up the 'Penetrating Channel' and 'Governing Vessel' (Chong & Du Mai), and when closing the practice bring the energy and 'shen' back down the front of the 'Chong' and 'Conception Vessel' (Ren Mai).
When one tucks their tailbone under and presses out their lumbar (opening Mingmen Point), this opens what is called the 'Lower Passage'. So from tip of the tailbone to lowest Thoracic vertebrae is the 'Lower Passage'.
Hollowing the chest and expanding the back of the thoracic vertbrae opens the 'Middle Passage' and is essentially the thoracic vertebrae.
Lengthening the cervical vertebrae and tucking the chin opens the 'Upper Passage', and is the cervical vertebrae and into the brain, roughly around the pituitary gland (mud pill palace) but represents the whole portion of the inside of the cranium.
So one is walking around the circle, quickly changing directions when needed, and it takes about 20 minutes for the energy to move from Huiyin point up passed Mingmen point. This phase and period of time is called 'A goat pulling a cart', as it's awkward, a little but clumsy as your legs are stiff. It's like watching a goat trying to awkwardly drag around a cart. And mentally you feel like the goat as you don't won't to be doing this, your mind wanders and you think of million other things you would rather be doing, but focus and endure this phase and don't really worry about exerting too much, but try focusing on the body requirements, and the martial requirements for the posture you're holding.
This awkward phase will quickly transition to where more blood is moving around and you want to start walking faster and faster. The rhythm and cadence is perfect and you just want to walk, almost run around the circle because it feels so good and stimulating. This is when the energy is moving through the 'Middle Passage' and is going past the area of your heart. It's crucial to not suddenly stop practicing during this phase, so pay attention to your breathing as you don't want to gas out or have your breath come up into your chest. This is where you can focus on and make it a cardiovascular or aerobic workout but know that you can't just stop. If you have to stop then it's really important to properly wind down and close the practice, which is about 10 minutes of walking, and still another good amount of time before you sit down or go do another activity. This phase is also the reason that it's really important to practice in a quiet place with no distractions, a calm, serene place and ideally the same place everyday as the heart area can get too excited, or rather, unbeknownst to you, pull the distracting sounds into your subconscious mind, which can cause mild (nightmares) to serious mental conditions or 'Shen disturnance' over time.
Going through the 'Middle Passage' takes about 20 minutes, but it also depends on the months or years that you've been practicing and your energy level. If you have a lot of excess energy or excitement that day, then you may find yourself wanting to spend more time going fast around the circle. This phase is called 'A Deer pulling a cart' and represents the picture of trying to harness a cart to a wild deer and it will just run as fast as it can until the cart breaks away.
As suddenly as you found yourself passing from the Lower into the Middle Passage, you will find yourself passing the Middle and into the Upper Passage. This will slow you down, and your body will feel heavy, strong, and powerful. Each step feels like crushing and plowing your way around the circle. There will be more strength in your arms and their Martial requirements can be increased. This phase is called 'An Oxen pulling a Cart' and it's the only animal that doesn't mind being harnessed to a heavy cart and were bred for the task. This can also be likened to a heavy plow and the Oxen is dragging it through mud fields to plant seeds in it's wake. This is where you are
truly doing the 'Mud-plowing step' (aka mud wading stepping). And it's taken you so long to get to this point that you want to make it worth and spend at least 20 minutes or more, in this phase, where you are truly strengthening and building increasing your martial skills, but mentally it's also where your mind is clearing out the muck, and in Western medical terms this may actually be activating the
Glymphatic system. This phase is where you are mentally alert, happy, content, and even though getting to this point was physically demanding, and you may have been tired before you began, you now feel fully rested, as if you just had a full night's sleep.
In Baguazhang we take advantage of this movement of CSF to benefit the physical demands of the martial practices but in many ways the mental and spiritual side of it is more important. And it's the spiritual side of the practice that makes it not something to be taken lightly, or done half-assed. If you only practiced for 30 or 40 minutes you may only be getting up to the phase where you're in the 'Middle Passage' and only bringing energy up to this point will have negative effects on your health and emotional state. You have to practice until you reach the 3rd phase because then gravity takes over and everything, on it's own accord, begins to drain down the 'Conception and front of the Penetrating vessel, back to the Dantian. [The other important requirement, in order to close everything down and energetically to bring this energy back around the front, it's important to press the tip of tongue into the roof of your mouth, right behind the hard palate where there's a little ledge and the soft palate starts. This is called 'Connecting the Magpie Bridge' and is important for bringing energy out of your brain. But this requirement should be done during the whole session, not just at the end.] And you will naturally feel when it's time to stop and then just do the closing practice for about 5 minutes. But don't really go do any striking or other martial practices for at least another 10-20 minutes because you just did one of the most powerful 'Daoyin' that there is and you should let your body go back to normal.
This is also the reason that skipping more than 3 days may begin to make you feel ill, or sick without it's daily Daoyin that it's grown accustomed to.
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