Tara is the most widely practised deity of Tibetan Buddhism after Avalokiteshvara, and the quality her devotees name first is speed. She is the one who answers quickly. Her name is connected with crossing over and with the star that guides, and she is addressed as a mother.
Her best-known form is Green Tara, seated with the right leg extended and the foot down on a small lotus, as though she is already rising to go. The posture is the doctrine: she is compassion in the act of moving, where Avalokiteshvara is compassion looking on. Her mantra, Om Tare Tuttare Ture Svaha, is recited for protection in travel, in illness and in fear, and is among the most commonly heard in the Himalaya. The Praises to the Twenty-One Taras is chanted daily in many households and monasteries, running through twenty-one aspects of her with their colours and functions.
She is said to have been born from a tear of Avalokiteshvara, shed when he saw that the suffering he was working to end was not diminishing. In another and more pointed account she is a princess named Yeshe Dawa who is told that her practice is admirable and that she should pray to be reborn male in order to progress, and who replies that in this form she has attained and in this form she will remain, and vows to appear only as a woman until samsara is emptied. The story is doing deliberate work.
White Tara is a distinct practice, associated with long life and healing, seated in full lotus, with seven eyes, one in each palm, one in each sole, one in the forehead, so that she watches in every direction at once. She is often practised together with Amitayus and Ushnishavijaya as the three deities of long life, on behalf of the sick and of teachers whose lives are wanted longer.