Karthik Masam is famous for the worship of Lord Shiva and Lord Vishnu.When full moon enters into Krithika the fiery planet, the month is termed as Karthikam. In such an auscpicious month, Chiluka Dwadasi/Ksheerabdi Dwadasi falls on 12th day. This day is also called as Chinuku Dwadasi/Thirthana Dwadasi/Tulasi Dwadasi/Yogeswara Dwadasi/HariBodhini Dwadasi.
Uthana Ekadasi falls a day before Chiluka Dwadasi. Lord Vishnu who was in cosmic sleep from Ashada suddhaa Ekadasi,wakes up on Karthika Ekadasi. Hence it is termed as HariBodhini Ekadasi.Ksheerabdi Dwadasi also signifies the beginning of Ksheera Sagara Mathana (Churning of theMilk Ocean).