Most of what I would have to add has been covered already.
In my bare limited experience the 3 tan tiens relate to the nerve ganglia, and act as "batteries" and resemble "force fields" (although I forget where I first heard that metaphor), while the chakras seem aligned/related to the spine...
There seem to be a number of other "large points" that have been described as "chakras" such as the Meng Men, and the energy centers of the palms, and the K1 point/bubbling well in the feet. How do the gua/kwa relate?
Bruce Frantzis make the case in his "opening the energy gates" book that there are a number of vorticies resembling chakras on the OUTSIDE of the body, although I'll admit that it's been at least 10 years since I read that book. In my own experience, and from my teacher I have made use of an 'energy center" that exists a few inches in front of the "third eye" point outside the skull.
I really like the Astral Dynamics information, and approach to this stuff as well. I was introduced to it last year, and thought that they brought it all together in a nice accessible way. I would recommend it to complete beginners over the hodge podge, hit or miss approach that I've been experiencing.
Has anyone else noticed that "subtle energy" reacts differently depending on the metaphore you're using? If I'm treating it as "prana", or "qi", or "ether", or "magnetic fluids" (ala Mesmer), I seem to have a different experience of it.
I am quite facsinated by the tought that physical structures, such as the fascia, bones, lymph, and nerves act as conduits, or possibly generate sublte energies.
great thread everyone thank you!