The "Shiva-Samhita" text defines the yogi as someone who knows that the entire cosmos is situated within his own body, and the "Yoga-Shikha-Upanishad" distinguishes two kinds of yogins: those who pierce through the "sun" (surya) by means of the various yogic techniques and those who access the door of the central conduit (sushumna-nadi) and drink the nectar.