According to the traditional Hindu beliefs, Lord Vishnu had several incarnations to eradicate Adharma or Sin from the face of this earth and establish the reign of Dharma.
This vrat or vow is celebrated on the shukla paksha of the Bhadra month according to the traditional Hindu calendar and in the month of August September according to the Gregorian calendar.
According to Hindu legends on this day, the 5 th incarnation of Lord Vishnu appeared on the face of this earth. He was born on the Shravana Nakshatra in this world.
Legend of Vamana
Lord Vamana is the 5th incarnation or Avatar of Lord Vishnu. The details of this are found elaborately in the Vishnu Purana and Shrimudagvad Purana. The great achievements and the tales of Vamana are extolled in these.
According the legends, once while the battles between the Devas and the Danavas were being fought, the Danavas or the Asuras became fraught with Lord Indra’s attacks and became unconscious. Bali, the King of the Asuras was amongst those who were the worst hit. Shukracharya, then gave Sanjeevani or life saving drug to all the Asuras.
After regaining consciousness, Bali went in an austerity drive and performed severe penances. He became more powerful than the Devas themselves. He got as a boon the trident, chariot and armor for his protection. With these he started reigning supreme on all the earth. He was performing 100 Ashwamedha yajnas, after the success of which he would have conquered Heaven too.
Lord Indra came to know of Bali’s desire and immediately sought an audience with Lord Vishnu, to tell him about the imminent danger facing all the devas and swargalok or Heaven. Lord Vishnu assured him of his intervention and decided to himself put an end to the tyrannous plans of Bali. As decided he plans to take birth in the womb of Aditi, the wife of Sage Kashyap. Accordingly, Kashyap send his wife to perform the Payo fast so that they are blessed with a son. In due course of time, Lord Vamana takes birth from the womb of Aditi. On the shukla paksha of the month of Bhadra, the child that is born is named Vamana, and he adopts Bramhacharya. In his endeavor to destroy the Asuras, Vamana was given deerskin by Sage Agastya, a Butea rod from Marichi, clothes ftom the Angiras, Umbrella from the Sun God, the sacred thread from Sage Bhrigu, the kamandal from Gurudeva, Aditi gave him his loin cloth, Goddess Saraswati gave him his Rudraksha and Lord Kuber bestowed on him a begging tray.
Vamana grew up and then went to see the Asura King Bali on the day when his 100th Ashwamedha Yajna was about to be held. King Bali pleased at having met a Brahmin on the auspicious day asked what Vamana wanted and promised to fulfill the same. Vamana asked for only 3 paces of land that he could measure by his own feet. Since Bali had already made a promise, he could not deny and allowed him to take the steps to measure out his land. Vamana then took his first step, which covered the whole world, with his second step Vamana encompassed the Heaven and took two of the places under him. Bali understood, and as there was no more places to take the third step, Bali offered his own head. Vamana then stepped on Bali’s head and subjugated him.
Lord Vishnu was pleased with Bali as he had kept his promise, so as a result asked him to make a wish which he wanted fulfilled. Bali asked of Lord Vishnu to be present in front of him day and night so that he can worship Lord Vishnu to his heart’s content.
The subjugation of Bali by Vamana is the victory of good over evil, of right over wrong, of truth over untruth. Thus the day of Vamana Dwadashi holds special significance to the devotees.
Rituals to be observed on Vamana Dwadashi
Devoted Hindus keep a fast from the 11th day of Bhadra till the 12th day of the puja. On the 12th day or the dwadashi, devotees wake up, take a holy bath and and worship the image of the Vamana. They stay awake the entire night and recite the Vishnu Sahasranama on this day Brahmin boys are invited and umbrella and other small gift articles are given to him.
There are certain temples dedicated to the Vamana avatar of Lord Vishnu, as the Vamana Temple in Khajuraho, the small temple in Cherukuru, the Vamana Moorthy temple in Thrikkakkara In Kerala or the Ulagalnatha (Trivikrama,Vamana) Perumal Temple in Kanchipuram in Tamil Nadu observe this day amidst somber prayers and deep dedication.