Bhishma Dwadasi, or Bhisma Dwadasi, is believed to be the day when Pandavas performed the last rites of Bhishma – the great grandfather in the Mahabharata. Bhishma Dwadashi 2015 date is January 31. The day is also known as Magha Shukla Dwadasi. Bhishma who had got the boon of Icha Mirthyu, or to die when he wishes, chose the 12th day in the month of Magha (January – February) during the Shukla Paksha (waxing phase of moon).
The popular belief is that Bhisma who was mortally wounded and was lying on a bed of arrows chose to leave the earth 58 days after the beginning of the Great War in Mahabharata.
Pandavas performed the last rites on the day on the banks of the River Ganga. In some regions people perform special rituals dedicated to the dead on the day.
There is a popular belief that offering Tarpan and Shradh on Bhishma Dwadasi day to ancestors is highly beneficial. Some people also perform Shradh in the name of Bhishma as he had no children.