On the eighth day of the black half of Bhadra (August - September) was born Shri Krishna, the eighth Avatar or incarnation of Vishnu. Therefore, this day is well known as Janmastami or Krishna-Janmashtami. This auspicious day of birth of Krishna, the direct manifestation of Vishnu himself is celebrated in all parts of India with clat and great enthusiasm. In the Bhagvad Gita Krishna declares: "All this universe has been created by me; all things exist in me", and Arjuna addresses him as "the super universal spirit, the supreme dwelling, the eternal person, divine prior to the Gods, unborn omnipresent". His life is celebrated in great detail in the Puranas like Harvamsha and Shrimad Bhagvatam. The circumstances in which he was born were quite peculiar and mysterious. He incarnated himself primarily to destroy evil and wickedness and to establish Dharma.
Janmashtami celebrations start right from the early morning with the bath in the sacred waters and prayers etc., but the climax reaches in the midnight with the rising moon, which marks the divine birth. On this auspicious day, strict fast is kept and broken only after the birth of Krishna at midnight. The temples and homes are decorated, scene-depicting Krishna's birth and his childhood pranks, etc., are staged with models both living and inanimate. Child Krishna's image is put into a richly decorated swing and rocked with a tender care all the day by the devotees. At night after birth, a small image of toddling Krishna is bathed in Charnamrita, amidst chanting of hymns, blaring of the conches, ringing of the bells and joyous shouting of "victory of Krishna".
In Braja Mandala, especially Gokula and Mathura, this festival is celebrated with great possible religious fervor and enthusiasm and the special deliberations of the day are relayed on the air. People from distant places congregate to Mathura and Vrindavan on this day to participate in the festival. The piety and fast observed on this day ensure birth of many good sons, and salvation after the death. Reading and recitation of the Bhagvatam and Geet Govindam are most recommended on this day.
Legends of Janmasthami
The demon king Kansa was a great and dreaded tyrant, but he loved his sister Devaki, and at her marriage with Vasudeva, he, out of great affection, drove their marriage chariot. Then, all of a sudden an oracle told him that eighth born of Devaki shall be the cause of his doom and death. At this he would have killed her then and there, but for the intervention of Vasudeva and their promise to give him over each and every child born to them. They kept their promise, and Kansa killed all of their seven children one after the other to a great suffering and grief of the couple. They were kept in the prison under strict watch and in chains and locks.
So Krishna was born as their eighth son in the prison cell. But it so happened, with divine grace, that the guards fell asleep, their chains loosened and locks and the gates of the prison cell opened. Vasudeva took the child Krishna to Nanda's house in Gokula and exchanged him for a baby girl born there to Yasoda. When Kana heard of the birth of girl child, he at once rushed to prison cell, and lifted the female child high, catching it by the feet and was about to dash her against the rock. When it slipped from Kansa's grip and assuming the beautiful form of the Divine Mother vanishing saying, "Wretch! The destroyer is flourishing in Gokula". There was a great joy and rejoicing in Gokula at the birth of a son to king Nanda and queen Yashoda. Yashoda was quite unaware of the exchange that had taken place during the night.