I am responding to a common question that was asked to me about why you would put one hand in front of or on top of the other in qigong or meditation positions where this is required.
First in my personal opinion, for most people its not that strongly important which hand goes on top or on bottom. Many schools of thought in the qigong world as well as the yoga field say the energetic anatomy of men and women on the left and right channels is different. One way that this is described in a lot of detail is that one side of the body is either the sun or the moon or the male and the female.
In the energetic schools that have this thought, they will then tell the man or woman to put one hand in front of or in back of the other hand based on either the right or left channels of the body. This is a practical matter and I had this discussion with many of the masters I knew. However, after all my explorations I came to understand that until a person is at an advanced stage and is very deliberately working with their left and their right channels it does not matter all that much.
At a very practical level there is one main point that does matter and may influence your choice. This is that most people’s bodies are slightly imbalanced, either the left or right side of their body where in many small areas some will be more or less stretched than the other. The less stretched side could be that way because of genetics, trauma, uneven stretching, or other activities accumulated over daily life.
Usually the side of the body that is dramatically less stretched is the one you want to put on top or in front because it will stretch that side of the body out. Why will this happen? It will happen because the tighter side of the body, by being put in the forward or top position, will naturally stretch it more.
If you are sitting in meditation and have your hands palms facing upwards (to the sky) that means that the less stretched side would be put on bottom. If your palms are facing your tantien the less stretched side would be the hand that is furthest from your body. What this will do is it will slowly cause your body to release so that both the left and right sides of your body will be equal. This will increase the degree of chi flow and motion of your nerves into the side of the body that is naturally compromised.
Beyond that important practical point, when you reach a much more advanced level of qigong and you are deliberately working with the left and right channels of the body, there are various ways that you would place the hands. This has to do with deliberately balancing out and affecting the energies of the left and right channels. To simplify this, most qigong or tai chi masters will say put one hand or the other in front in general, however, the truth of the matter is much more complicated as you can see.
Although a teaching sound-bite may not be false, it is also may not be completely true. Each circumstance may require a different approach to achieve the results your are after.