Hatha Yoga Traditionnel
In Sanskrit yoga-nidrâ means yoga of the sleep.
Yoga it is the union, the union of the consciousness and the energy, the visible and the invisible.
The sleep it is the unconscious.
The yoga it is the awareness, the clarity(brightness), the lucidity, the observation of what escapes the common attention. Yoga-nidrâ it is thus the infiltration, the penetration of the consciousness in this dark, opaque, sluggish zone that is the sleep.
In the yoga classic yoga-nidrâ does not exist, it is a purely tantric "technique", a technique to part, in margin, and that nevertheless asks for a big habit of the prânâyâma, the concentration and especially the meditation. In a way, yoga-nidrâ is situated at a level raised(brought up) in the tantric "hierarchy". In other words we cannot really make with profit that at the end of some years of yoga.
The objective of yoga-nidra is to invest(surround) consciously the sleep.
Through good times and bad, we sleep on average eight hours on night, that is a third(third party) of our life. A third(third party) in which we are unconscious of what takes place, of whom we are and of what we make. A third(third party) of blackout, torpor, oversight(forgetting).
Imagine, over eighty five years of life it represents almost twenty five years! Twenty five years in the course of which we were aware(conscious) of nothing, or almost, except some flashes of lighting in the dreams! Not even of what to produce some light for quarter of an hour in eighty five years!
Understand(Include) that it is unbearable for a yogi in search of consciousness, and for a not too much dulled human being.
We are going to find 3 types(chaps) of practices:
Those of day, those of night itself and the sessions.
The common point is that these three types(chaps) of practices appeal to completely classic techniques but they are differently declined for the needs of the cause, those of yoga-nidrâ. They lean on an observation, a perception(collection) and one felt intense of the senses(directions), mainly a touch, a view(sight) and a sound. The sessions of yoga-nidrâ are nothing else than meditation tantric classic in whom(which) are added some specific elements to the yoga-nidra which favor the tiredness and modified breaths, either lengthened(stretched out), or slow, or disintegrated which allow to infiltrate the space in which occurs the passage of the day before(watch) in the sleep. These sessions use what we call the tantric imagination, the sorts of scenarios based on the sensations.
It is obviously necessary to know how to release(leave), give way without losing any attentiveness and in these zones between two, at twilight, the day before(watch) and sleep, consciousness and oversight(forgetting), the control(master's degree) of the prânâyâma, the concentration and the meditation is useful, doubtless indispensable to cross(exceed) the passages usually so well kept(guarded) in the waking state.
Extract of Christian Tikhomiroff's article, nâtha yogi