By Swami Harshananda
Sukṣmakriyā literally means 'the subtle process'.
It is the fourth step in the practice of Layayoga. It consists in withdrawing the mind from the external sense-objects and concentrating on the light between the eyebrows. This is also called jyotirdhyāna.
- The Concise Encyclopedia of Hinduism, Swami Harshananda, Ram Krishna Math, Bangalore