Caṇḍālī

caṇḍālī (T. gtum mo གཏུམ་མོ་; C. zhantuoli), known as tummo in Tibetan, is a tantric yoga practice that entails the manipulation of the subtle energy of the body in order to produce states of bliss and clarity. This practice also generates physical heat within the body, which in the Tibetan tradition is taken as a sign that the practice is being done properly.

This practice typically employs a combination of physical postures (asana), breathing exercises, and visualizations; these techniques are used to draw the subtle energy of the body into the "central channel," in order to generate bliss.

In the English language, this practice is known as "inner heat," "mystic heat," "psychic heat," etc.

This practice is one of the six yogas of Naropa.

Traleg Kyabgon states:

Mystic heat yoga or tummo is the most important of the [six] yogas in the Kagyu lineage. It is about transforming ourselves on the physical level and by doing so, we learn to ignite the original, innate wisdom mind. The fire that we generate in the body through tummo practice literally ignites the wisdom mind, which is inherent within us. Instead of only using the mind and different kinds of meditation practice, working with our different mental states, and so forth, by using our own body, and by generating this heat, we can ignite the luminous mind, the mind of clear light, ösel as it is called in Tibetan.

Contemporary American scientist Herbert Benson studied this practice in coordination with the 14th Dalai Lama. He recorded the following observation:

On another expedition, we sent a film team to Minali. There we were able to study monks who had spent an entire year practicing tumo. On a night considered to be the coldest of the year, the first full moon of the period, in a room temperature of 48°F, just a few degrees above freezing, these monks dip sheets into icy water and then, taking his dripping wet sheets, which measured some three by six feet, wrapped there essentially naked bodies in them. You and I would shiver uncontrollably and perhaps even die if we did this, but here, within 3 to 5 minutes the sheets started to steam and within 45 minutes were completely dry. The monks repeated this process twice before dawn. It was truly remarkable.

Sources

• Benson, Herbert (1991), "Mind/Body Interactions including Tibetan Studies", in Goleman, Daniel; Thurman, Robert A. F., MindScience: An East-West Dialogue, Wisdom Publications 
• Traleg Kyabgon (2020), Vajrayana: An Essential Guide to Practice, Shogam Publications 

Further reading

• Lama Thubten Yeshe, The Bliss of Inner Fire, Wisdom Publications, 1998.
• tsan_da_li, Rangjung Yeshe Wiki