Kantha Sashti is the well known story of how lord Lord Muruga defeated Surapadma. During this time, devotees partake in a strict fast.
Kantha Sashti is one of the strictest fasts there is in the Hindu religion. Devotees start their days off showering every morning. Once they are done showering, they have prayer. During prayer, they must sing Kantha Sashti Kavasham. This song must only be sung only during Kantha Sashti. Once morning prayer is done devotees go about their regular day, however they are forbidden to eat. At night devotees do another prayer, where they sing Kantha Sashti Kavasham again. Once the night prayer is over, devotees will break their fast. Some devotees will break their fast with rice and vegetarian curry, others will break their fast with fruits and milk, and rare devotees will break their fasts by only eating whole black peppers. On the last day of Kantha Sashti, on Sura Samharam, devotees will not eat at all. They will only eat the following day, early in the morning. This day is known as Paranam.
When a devotee decides to fast for Kantha Sashti, they must continue this fast for 6 consecutive years. After the 6 years, devotees must take a year off where they do not fast for Kantha Sashti. Once they take the year off, if they wish, they can continue fasting for Kantha Sashti or they can completely stop.
Kantha Sashti is a fast that requires commitment and will power. Devotees who decide to partake in this fast, do it with their full heart and ability.