It is a branch or recension of the Krishna Yajurveda. It forms part of the Katha-Sakha Brahmana of the Krishna Yajurveda. The Kathopanishad is divided into six Vallis. Valli literally means a creeper. A Valli, like a creeper, is attached to the Sakhas or Branches of the Veda. Valli is used in the same sense as Parvam, joint, shoot, branch, i.e., a division. This Upanishad is also divided into two Adhyayas (chapters) of three Vallis each.
The narrative is taken from Taittiriya Brahmana (3-11-8) with some variation. The same story is told in the Taittiriya Brahmana, only with this difference, that in the Brahmana, freedom from death and birth is obtained by a peculiar performance of a sacrifice, while in the Upanishad, it is obtained by knowledge only.
The story is as follows:read on..
A few verses from this Upanishad occur in the Bhagavad Gita.
The comparison of the body with a car or chariot, the soul with the Lord of the chariot, the intellect with the rider, the mind with the rein, the senses with horses, the five objects of the senses with the roads, is indeed very beautiful.
In this Upanishad, the way to attain Self-realisation is fully treated.
From such passages as, “This Atman is difficult to be known, It is very subtle, It cannot be obtained by arguing”, it is quite evident that revelation or direct intuition (Aparoksha-anubhuti) is the source of the knowledge of the Self.
From such passages as, “A wonderful teacher is required”, “Arise, awake, having reached the excellent teacher, learn” (III-14), “How can this Atman be realised otherwise than from those who say that It exists” (VI-12), it is quite clear that a realised Guru is necessary to lead the aspirants in the spiritual path.
From the 11th Mantra of the 6th Valli, this Upanishad recognises the necessity of Yoga as well. This Mantra says: “The firm control of the senses they regard as Yoga. At that time one becomes vigilant, for Yoga is acquired and lost”.