Jai Sriman Narayana !!
Varaha Puranam describes Kalki Dwadashi Vrutham, which falls on the eleventh day of bright half of the month - Badrapad. As a part of the austerity the worship Lord Kalki, fast on the day of Ekadashi and breaking the fast on the Dwadashi day are treated as auspicious. The worshipped idol should be donated to a Brahmin with alms on the day of Trayodashi brings abundance of devoutness.
Jai Sriman Narayana !
