Dhanatrayodashi Rituals

Though Diwali starts with Vasu Baaras the actual momentum is gained only by Dhanatrayodashi or Dhanteras. Rangolis, Diyas, Muhurat shopping and poojas mark the day of Dhanteras. 

Mythological background : As the Devas and Asuras churned the ocean on milk, Dhanvantari the divine healer finally manifested himself with the pitcher of Amrita. He was none other than Vishnu. Dressed in fine raiment, carrying the conch, discus, leech and the pitcher of Amrita he destroys the physical and spiritual ailments of the world. Dhanatrayodashi is celebrated to commemorate the advent of this form of Lord Vishnu. Those who worship him on this day will be blessed with good health and good luck all year round.  Dhanvantari is the patron deity of Ayurveda. 

Rituals : 

1. Dhanvantari Pooja
Most Ayurvedic physicians perform Dhanvantari pooja on Dhanatrayodashi. There is also a sacrifice called Dhanvantari Yaaga performed for good health of the family and purification of the premises. Those who cannot do this pooja can worship Lord Dhanvantari by chanting the following mantras during the evening prayers on Dhanteras.

धं धन्वंतरये नमः | Dham Dhanvantaraye Namah .
ॐ नमो भगवते धन्वंतरये अमृतकलशहस्ताय सर्वामयविनाशनाय त्रैलोक्यनाथाय श्रीमहाविष्णवे नमः  ॥
Om namo bhagavate dhanvantaraye amrita-kalasha-hastaaya sarvaamaya-vinaashanaaya trailokya naathaaya shree-maha-vishnave namah
Om. I bow time and again to Lord Dhavantari who carries the pitcher of Amrita, who destroys all ailments, who is the Lord of the three worlds and is (none other than) Mahavishnu. 
 Dhanatrayodashi is in a way a day to honour our physicians who are custodians of our health.

2. Yamadeepadaan : This is a small but important ritual to be done on Dhanatrayodashi for the health of the family and to avert untimely death. A lamp made of wheat flour mixed with turmeric , filled with sesame oil and a cotton wick is to be lit outside the main door of the house with the flame facing south. This lamp is offered to Yama, the God of righteousness and death with the following mantra 

मृत्युना कालदंडाभ्यां कालेन श्यामया सह | Mrityuna kaala-dandaabhyaam kaalena shyaamayaa saha 
त्रयोदश्यां दिपादानात् सूर्यजः प्रीयतां मम || trayodashyaam deepa-daanaat sooryajah preeyataam mama 

May Kaala, Lord of death who is born of the Sun God(ie Yama) , who wields the sceptre of mortality along with his consort Shyaama be pleased with this offering of a lamp made on this thirteenth day (of the dark half of Ashwina).

Customs : Worship of wealth.
At dusk as the oil lamps are lit, people place new utensils, money, ornaments on an altar. Coriander seeds (dhaniya) is put in these vessels. Worship is offered in the form of flowers, sandalpaste, incense, lamps and sweets. These utensils are used from next day. People buy new clothes and utensils on Dhanteras.