nyāsa (न्यास) means "applying", "placing", "fixing"

In the process of this ritual, fingers of the right hand, folded into certain mudras, are applied to different parts of the body with the simultaneous repetition of certain mantras.

Nyasas are often used in tantric rituals, and besides it – before pranayama. Through the performing of nyasas, sadhaka activates (or calls, establishes) certain energies in his body. There are many nyasas, they differ depending on the nature and depth of worship. For example:
  • Rishi-nyasa
  • Kara-nyasa
  • Anga-nyasa
  • Varna-nyasa
  • Pada-nyasa
  • Dashatattva-nyasa
  • Matrika-nyasa

and others.

In addition, there are different orders for performing nyasas: 
  • Srishti-krama-nyasa (nyasa in the order of creation)
  • Sthiti-krama-nyasa (nyasa in the order of preservation) 
  • Samhara-krama-nyasa (nyasa in the order of destruction)

Also nyasas are external - bahya-nyasas, and internal - antar-nyasas.