Tonglen — Taking and Sending
Tonglen (taking and sending) is the Vajrayana practice of compassion cultivation — breathing in the suffering of all beings and breathing out happiness and liberation — reversing the self-grasping habit at the root of suffering.
Tonglen (Tibetan: gtong len — 'sending and taking') is one of the most profound compassion practices in Vajrayana Buddhism, rooted in the Bodhicitta (enlightenment mind) teachings of the Mahayana and elaborated in the Lojong (mind training) tradition. The practice involves: inhaling while visualizing the suffering of all beings (starting with specific beings, expanding to all) as black smoke entering the heart and being transformed there; exhaling while sending out light, happiness, and all positive qualities to all beings. The practice directly challenges the fundamental self-protective habit of ordinary mind (taking in pleasant things, pushing away unpleasant things) by deliberately reversing it — willingly taking in suffering and giving away happiness.
Breathe in the world's suffering. Breathe out happiness and peace. This reversal of selfishness is the fastest path to Buddhahood.
Tonglen — breathing in others' suffering and breathing out one's own well-being — belongs to the Lojong tradition brought to Tibet by Atisha and rooted in Shantideva's Bodhicharyavatara teaching on exchanging self and other.
Bodhicharyavatara