Bhishma Panchak has great importance in Hinduism . In the Puranas, 'Bhishma Panchak' fast is said to have special significance in the month of Kartik . This fast Karthik month Shukla side of Ekadashi begins and the full moon lasts. Bhishma Panchak is also known as ‘Panch Bhikhu’. Karthik bath is given a lot of importance in the scriptures . Hence, all the people who take bath in Kartik do this fast. This fast was observed by Bhishma Pitamah , hence it became famous as 'Bhishma Panchak'.