The festival is in memorial of a fight fought in 1705-06 by Guru Gobind Singh against the grand forces of the Moguls and pays tribute to the forty Sikhs who achieved martyrdom on this day.

One of the largest Sikh fairs, it is held in the middle of January on the Makar Sankranti day. The festival is spread over three days. On the first day worshippers bathe in the sacred tank. The second day is a procession (mohalla) to the three holy mounds which lie to the north-west of the town, namely, Rikab Sahib, Tibbi Sahib, and Mukhwanjana Sahib. Rikab Sahib, commemorates the spot where the Guru's stirrup broke.

Tibbi Sahib crowned with a Gurudwara, is the mound where Guru Gobind Singh stood and aimed his arrows at the imperial forces. At Mukhwanjana Sahib, Guru is said to have cleaned his teeth with a tooth-stick.

After offering prayers here, the devotees then come back to visit Tambu Sahib where the Guru's tent was pitched before the fight started, Shahid Ganj, which is the samadhi of the forty martyrs, and Darbar Sahib, where the Guru held his darbar after the cremation of the slain.