Kosha in Sanskrit means layer, sheath, or subtle body.  It also means, “to unfold.”  The koshas were first written about in the Upanishads to explain the five layers of subtle energy from the outer, physical body to the inner core.  The layers exist like the layers of an onion, becoming more subtle until the center layer is reached.  The five koshas are:

1. Anna-maya kosha: the physical body, skin, muscle, tissue, and bone.  The expression of this kosha shows up in the movement and workings of the body.

2. Prana-maya kosha: the vital body, or breath.  In this layer is the circulation of the breath and of the life-force energy.

3. Mano-maya kosha: the mental body.  This kosha encompasses the nervous system and is expressed through thought

4. Vijnana-maya kosha: conscious, or intellect.  This kosha observes, and is aware.  It is also known as the “witness” which gives us the ability to stand outside the self and watch without judgment or attachment.

5. Ananda-maya kosha: bliss.  This is the innermost layer where we live in present-moment awareness, without thought, sensation or judgment.  We become joy rather than just feeling it.