Good, these are good questions.  Well done, somebody has a brain. So what are the answers then, not bullshit talk ... what are the actual answers.   Chen Training For Chen, it is not a "meridien stimulation".  They are training the Dantien Qi to leave the belly and circulate through the body and then to return to the Dantien, cultivating a qi body of circular Qi-tracks.  They have a particular training plan which involves 10 tracks in the basic patterns, and 10 other tracks in the advanced pattern. The result is a regular 3 dimensional qi pattern - like an atom with the electrons circulating around.  It is simple circular and very contained. It is a spiritual art because it cultivates the Dantien centre directly. Those are some answers that come from the CX tradition which are detailed in  that "Chen" book with diagrams and training sequences.  This is one of them.     Dantien-mind Training After the 20 tracks are learnt from ChanSiGong, then the long forms are learnt; each form is divided into 80 or so mini-forms ... in each mini-form the Qi leaves the Dantien, circulates, and returns to the Dantien.  The movements are of many shapes which allows the energy-mind of the Dantien to train itself to perform any kind of shape.  This is similar to using your mind to do many types of numerical calculations, addition, multiplication and so on.  The different movements train the energy-mind so that it becomes fully trained. Eventually the energy-mind moves on its own from your will-instinct.   Phases in Internal Arts Training The book describes excellently this step by step phased training which can be used for all of the internal arts. The book describes much more than I can put here.   Yiquan Training For instance in Yiquan there work with the Dantien field of the body as a whole, not with the circulation of the Dantien; and in Yiquan there is a lot of Awareness practice coming from the head so they train Awareness plus the body field of qi.  In Chen there is not much need for Awareness training as the Belly is trained to work on its own.   Liuhebafa Style For LHBF it is very different from those styles.  Firstly because it is fragmented it is important to remember that many people have lost the details of the art and don't know much what they are doing. But you can certainly say that it involves lost of vertical compression/depression that is the released horizontally, it is the exchange of qi from vertical to horizontal.  In other words you build up qi pressure vertically ... and then release horizontally.  Some of the movements are like that.  Other movements are splitting, and reconnecting, like tying a bow.  Another aspect may be about circulating the water element which is how the opening movement is often done open the lake below and rising to above the head; there is also kind of pulse or wave of energy rolling through the body which is water esque. Whether it is Dantien based or not I cannot say, some movements do appear to exit and return to the Dantien others do not.   Pure LHBF vs Mixed LHBF It may be that there was a pure LHBF, but that other people are using LHBF as a container to add together various techniques from Bagua and Xingyi, and practice them all together - which makes it hard to see the pure style.  I notice that some movements that are done Xingyi-fashion are done non-Xingyi by other schools, so I think that was added in and not the pure style : Wang Xiangzhai used to tell his students to sometimes train LHBF (identifying it as a different style), so I think those students left some Xingyi and Yiquan aspects in LHBF, which are not pure LHBF.  The fact that WXZ recommended LHBF training on the side means that it is a compatible tradition and must have similarities with Yiquan; imo Chen is not compatible as the tight circular movements don't play well with LHBF. Also there is this rising palm-up spear-hand that seems to be foundational for the style and is in many moves; again showing the vertical movements that are foundational for the style.   I don't know of any Alchemy for Chen.  For LHBF I don't know of any either.  It doesn't look alchemical to me.  Often people imagine Alchemy because they don't understand that it is simpler than that.