Samatha meditation is based on mindfulness and the path from calm (samatha) to insight (vipassanā) so it is very important so you must make sure you are relaxed and feeling comfortable when meditating.
There are two important points in meditation -- the body and the mind, so you will need to make sure you body feels good when you meditate.
It is important to keep the body straight so that the subtle channels of the body will be straight, too. If these subtle channels are straight, then the subtle energies within these channels will circulate freely. It is said that the mind is like a horse riding the circulation of the subtle energies of the body. When it is riding this energy freely, it is relaxed and peaceful.
The fivepoint description is usually used to help with this:
- The first point is that the body should be straight and upright. It
should be "as straight as an arrow" which means one's back should be
straight and one shouldn't lean forwards, backwards, or to either
- The second point is that the throat should be slightly bent downwards
like a hook. There are two subtle channels inside the throat, and if
they are bent slightly forward, the energy will circulate in them
reducing mental agitation in one's meditation.
- The third point is that the legs should be crossed in "patterns of
latticework" which means that the legs should be kept in a crossed
position. If one can put them in the full lotus posture, good. If
not, simply cross them in the half lotus posture.
- The fourth point is the body should be "gathered together like
chains." After straightening the body, lock it in that position as
with iron shackles. The way to do this is to join the hands, placing
them the width of four fingers below the navel.
- The fifth point is to keep one's mind and body reasonably tight
exerting a certain amount of effort so the body and mind are composed
and focused. This is compared to one's tongue when one, for example,
pronounces the Tibetan letters "li" and "ri" which requires a certain
amount of tension in the tongue. In the same way, one should always
maintain a certain amount of effort and alertness in the body and
The great teacher, Marpa, said that there are many different instructions on meditation posture, but he preferred this fivepoint posture saying that if one could keep the body in this posture, the subtle energy circulating in the body would be ideal and would actually circulate though the central channel of the body.