It is called the "Crown Jewel of Yoga". The Yoga Chudamani Upanishad belongs to the Sama Veda. It has 121 verses.
As the name suggests it is meant for the yogis who seek liberation and deals with the practice of yoga for self-purification. The knowledge contained in the Upanishad helps the yogis to stabilize their minds and experience self-absorption. According to the Upanishad, Pranayama (breath control) should be practiced while chanting Hamsa mantra. It should be chanted twenty one thousand and one hundred times. The mantra called Ajapa mantra has the ability to cleanse all the sins and grant salvation. It also awakens the Kundalini. The Upanishad explains the connection between Kundalini and Sushumna Nadi in the neck region. It is through Sushumna Nadi only Kundalin reaches the top chakra in the head. The gate to this should be opened by a yogi only through Kundalini. Para Brahman is the Universal Self and Para Shakti manifests as individual souls. She is the source of the five elements which are ruled by the five aspects of Shiva. the Upanishad also lists the elements, tattvas, the four states of consciousness, and bodily organs ruled by different deities. The soul is of the form of Aum. It represents the triple aspects of creation. Pranayama is the repetitive practice of pooraka, rechaka and kumbhaka in a specified manner. The Upanishad also lists the benefits of practicing pranayama, pratyahara and asanas.The following is an original translation of the Upanishad by P.R. Ramachander. Hope it will help you to understand the meaning and significance of the Upanishad and the practice yoga in spiritual liberation.