Significance and legend
Shat means six and tila means sesame. In the Bhavishyottara Purana, the sage Pulastya explains to Dalbhya, and Krishna to Yudhishthira, that on this Ekadashi sesame should be used in six ways: bathing with sesame water, rubbing the body with sesame paste, offering sesame in the sacred fire, offering sesame water to ancestors, eating sesame, and giving sesame in charity. The story told is of a pious Brahmin woman who fasted and kept vows constantly but never gave food in charity. To test her, Vishnu came to her door as a mendicant. Annoyed, she placed a lump of clay in his begging bowl.
By the merit of her vows she reached heaven after death, but found herself in an empty house, with no food or grain. Vishnu told her that because she had never given food, she could receive none. He advised her to listen to the glories of Shattila Ekadashi from the divine women who would come to visit her, and to observe the fast. She did so, and her house was filled with grain and wealth. The story teaches that fasting must go together with generosity.
How Shattila Ekadashi is observed
Devotees bathe with water containing sesame, apply sesame paste, offer sesame in homa, give sesame water to ancestors, eat sweets made with sesame and jaggery, and donate sesame, blankets and food to the needy. Vishnu is worshipped with tulsi, sesame and lamps, and many keep the fast without grains. Night vigil is recommended. The fast is broken on Dwadashi after sunrise within the parana window, often with a preparation containing sesame.