Like the illusory face of this appearing world,
The movement of mind is not touched by artifice;
It is not altered by action, freedom, or realization.
To remain in the depths of mind free of reference is known as mahamudra.
Within the Kagyu lineage, the practice of mahamudra is the deepest form of meditation. It is deceptively simple to describe and quite difficult to practice. Mahamudra practice could be described as remaining settled into the nature of mind, immersed in its nature that is awareness and emptiness inseparable, not touched by artifice, which means that there is no effort to do anything, and free of reference, which means that the mind is not grasping at anything at all. If you were working with this verse, you would first memorize it and reflect on its meaning until it became very clear. Then resting in meditation, you would float the verse in your mindstream, keeping a gentle focus, much as a koan is held. Then, after a while, you would let it go and rest in the space it has opened out, free of referent or mental activity. When thoughts arose again, you would fold them into the verse, which would become your referent again, and so you would continue, naturally shifting between resting in meditation and reflecting on the verse---Michele Martin, from Music in the Sky: The Life, Art and Teachings of the Seventeenth Karmapa, Ogyen Trinley Dorje
