Holika Dahan — Chhoti Holi — falls on the Purnima of Phalguna, the night before the Holi of colours. A bonfire is lit at the pradosh hour after sunset, and the community gathers around it to burn the effigy of Holika and, with her, the year's accumulated evil and ego. The next morning's play of colour is the release that follows the fire.

The fire is the point. Holika, the demoness who could not burn, was consumed, while Prahlad, the child who held only to Hari, walked out untouched. The Holika Dahan is the yearly re-enactment of that reversal: that devotion outlasts power, and that what is impure is what the fire finally takes.

Because it falls at winter's end, the bonfire is also literal — the burning of the old, dry leavings of the cold months, and new grain roasted in the flames as the first offering of the coming harvest.

Hiranyakashipu, a demon king granted near-invincibility, demanded to be worshipped as god. His own son Prahlad worshipped only Vishnu. Enraged, the king tried again and again to kill the boy, and each time Vishnu preserved him. At last he turned to his sister Holika, who had a boon that fire could not harm her: she took Prahlad into her lap and sat in a blaze. But the boon failed her when misused — Holika burned to ash, and Prahlad, chanting Hari's name, was untouched. The night's fire is her pyre; the next day, Vishnu as Narasimha ends Hiranyakashipu himself.

The spring fire-festival is very old — references to Holaka appear in early dharma texts and the poet Kalidasa and others describe a spring festival of colour and revelry. Al-Biruni in the eleventh century records Holi among the festivals of India, and Mughal-era paintings show it played at court. The bonfire and the play of colour are two halves of a rite that predates any single telling — the Prahlad story gives the fire its meaning, while the colour carries the older spring-fertility revel.

The Prahlad and Holika narrative is told in the Bhagavata Purana (Canto 7) and the Vishnu Purana, leading into the Narasimha avatara. The observance of the Holika fire and the spring festival is set out in the dharma-nibandhas and the Purana chapters on Phalguna, which prescribe the pradosh-time lighting and the pradakshina of the fire.

Holika Dahan falls at the seam of winter and spring, when the harvest is drying and the air still carries the last cold. The communal bonfire cleared the fields' dry waste and, folk wisdom held, the heat and smoke thinned the season's insects and infections at the very moment they multiply. Roasting the new grain — gram, wheat ears — in the fire was both an offering and the first eating of the crop.

Hiranyakashipu won a boon that he could not be killed by man or beast, indoors or out, by day or night, on the earth or in the air, and grew so proud that he forbade the worship of any god but himself. Yet his son Prahlad, from the cradle, spoke only the name of Hari. The king coaxed, threatened, and at last tried to kill the boy — flung from cliffs, given poison, thrown among serpents — and every time the child came through unharmed, Hari's name on his lips.

At last Hiranyakashipu called his sister Holika, whom fire could not burn, and had her carry Prahlad into a great blaze. But a boon misused turns on its holder: Holika was reduced to ash and the boy walked out untouched. That night the fire is her burning. The following evening — at the seam of the boon, on a threshold, at twilight, in his lap — Vishnu came as Narasimha, neither man nor beast, and ended the tyrant, and Prahlad's faith was answered in full.