Bhoto Jatra is an annual cultural cum religious ritual of displaying the black jewel-studded bhoto (vest) believed to be of then Nagraj, the serpent king.
After the two chariots arrive in Jawalakhel, astrologers choose an auspicious date to hold the Bhoto Jatra festival. On the appointed day in the presence of the head of state, a government official climbs on to the chariot and holds up a jewel-studded black vest from the four sides of the chariot so that all the people gathered around can have a look at it.
The head of the State attends the function. The government announces public holiday in Kathmandu valley on the occasion each year.
According to legend, a Jyapu (Newar farmer) lost the vest which he had received as a gift from the serpent god Karkotaka Naga for doing him a favour. One day, the farmer had come to Jawalakhel to watch the chariot pulling festival where he saw someone wearing his missing garment.
A quarrel developed over the vest, and since neither party could prove ownership, it was agreed that the undershirt would be kept with Bunga Dyah until the rightful owner comes to claim it with adequate proof. Since then, the vest has been shown to the public annually as a call to potential claimants to step forward.
Photo: By Nirmal Dulal - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=14712233