The baci ceremony is one of the main ceremonies within Lao culture.
In traditional belief, the human being is an aggregate of 31 to 32 organs. Each of these organs has a kwan to watch over and protect it. But the kwan, as a form of energy, has a tendency to 'wander' and so it is important to call them back to a body from time to time, securing them in place and establish equilibrium for maximum health.
The organs tend to be grouped in fives for easy memorization:
- Hair of the head, hair of the body, nails, teeth, skin
- Flesh, sinews, bone, marrow, kidneys
- Heart, liver, membranes, spleen, lungs
- Bowels, intestines, gorge, dung, brain
- Bile, phlegm, pus, blood, sweat, fat
- Tears, grease, snot, spittle, oil of the joints, urine
In advanced Buddhist philosophy these organs are particularly contemplated in Patikulamanasikara meditation.
For further details, The Lao Heritage Foundation has a good overview of the specific elements of a baci ceremony.