A Maha Mrityunjay Jaap Trimbakeshwar sitting is a long, carefully counted recitation of one of the best-known Vedic prayers to Lord Shiva, offered in the Jyotirlinga town whose name is tied to the mantra's first word. That word is Tryambaka, the three-eyed one.
The mantra appears in the seventh book of the Rigveda (7.59.12) and again in the Yajurveda:
Om tryambakam yajamahe sugandhim pushtivardhanam, urvarukamiva bandhanan mrityor mukshiya maamritat.
In plain words: we worship the fragrant three-eyed Lord who nourishes all beings. As ripe fruit slips easily from its vine, may we be freed from the bonds of death, and not be kept from immortality.
Mrityunjay means the one who overcomes death, and devotees often read the mantra as more than a prayer for a longer life: it is also a prayer to be free of fear and attachment. Popular stories connect it with the young devotee Markandeya, whom Lord Shiva is said to have protected. Such stories speak of devotion; they are not a promise about anyone's health.
What sawa lakh means
Sawa lakh is the traditional way of saying 1.25 lakh, or 1,25,000. In a sawa lakh Mahamrityunjay jaap, the pandits together complete that full count over several days, keeping track on a mala, and each day's recitation is dedicated to the sankalp made in your family's name.
Faith and medical care
This jaap is a prayer. It does not replace medical treatment, and nothing on this page is medical advice. If someone in your family is unwell, please keep following the doctor's advice and continue their medicines, and see the jaap as prayer offered alongside that care. Maha Mrityunjay puja benefits are described here as traditional beliefs, and no one can promise a particular result.
Related pujas
You may also want to read about the Rudrabhishek puja, which centres on the abhishek of the Shiva linga rather than a counted mantra. If your concern arises from a horoscope, see the Rahu Ketu puja, and if it concerns your ancestors, see the Pitra Dosh puja. Guruji can tell you which observance fits your intention.