These elements are brought together in the practice of tantric deity yoga, which involves visualizing the deity's body and mandala, reciting the deity's mantra and gaining insight into the nature of things based on this contemplation. Advanced tantric practices such as deity yoga are taught in the context of an initiation ceremony by tantric gurus or vajracharyas (vajra-masters) to the tantric initiate, who also takes on formal commitments or vows ("samaya"). In Tibetan Buddhism, advanced practices like deity yoga are usually preceded by or coupled with "preliminary practices" called "ngondro", comprised of five to seven accumulation practices and includes prostrations and recitations of the 100 syllable mantra.