The third day (Tritya) of the waxing moon (shukl paksh) of the month of Vaisakh is an auspicious day. It is believed that the Satyug and the Treta Yug both began on this day and so it is very auspicious to begin any new ventures and businesses on this day. Any act whether it is a fast, worship, austerities or charity, carried out on this day are believed to be very fruitful.
This day is considered even more auspicious if it falls on a Monday or under the planet Rohini. The Lord Vishnu is invoked on this day by enthroning his image or his picture and by offering of water soaked grams, gram pulse and crystallized sugar and by sprinkling Tulsi water while performing Aarti. Many people also take a dip in the river Ganga on this day. Different kinds of things are given in charity and can be, rice, salt, ghee, sugar, vegetables, tamarind, fruit and clothes.
In Mahabharata, Sri Krishna explains the significance of this day to Yudhistar in the following manner. He describes this day as being most pious and is called `Yugaadi Trity’ because Satyug commenced on this day. Laying stress on the importance of the day, Krishna narrated the story of a poor godly Brahmin, who in spite of his poverty and having a big family to support, never shirked his religious duties and good actions. He observed this day with great faith and piety every year and as a reward for his faith became the king of Kushavati in his rebirth.