Hamsa Upanishad belongs to Sukla Yajur Veda.
Gautama asked Sanath Kumara to explain the way to obtain Brahma Vidya, the realization of God.
Sanath Kumara replied that Brahma Vidya could be obtained through Hamsa Vidya.
Hamsa denotes the Soul. Paramahamsa denotes Brahman, the supreme God. The Supreme God is in everything as Fire resides in Oil or Oil resides in Oil-seed. Brahman pervades all. Paramahamsa pervades Hamsa. Hamsa literally means “That am I”. There exists nothing other than Isvara or God. By Hamsa Vidya, Soul realises that he is the Supreme God. The realization of God in Self is Hamsa Vidya.
The process of Hamsa Vidya is explained. The Yogi should Press the Anus, force the Prana upwards from Muladhara, circumnavigate the six-petaled Svadhisthana thrice, reach the Manipura, go beyond Anahata, hold the Prana under control in Visuddhi, enter Anja, meditate upon Paramahamsa and then attain Nirvikalpa Samadhi. Drink the nectar generated by the commingling of Moon, Sun and Agni or fire, then enter the Brahmarandhra or thousand-petalled lotus. There meditate on Trimatra Turya or Turya-Turya. Then the yogi becomes devoid of external form. This is the Paramahamsa resembling ten millions of suns, by whose radiance the entire world is completely enveloped.
This needs explanation and understanding of Chakra and Kundalini.
We will explain in detail in our next post: hamsa-upanishad-hamsa-vidya-chakras