Bohaggiyo Bishu is the most fascinating spring festival of the Deoris of Assam, one of the four divisions of the Chutiyas, who are believed to have been members of the great Boro race. The term 'Bishu' might have originated from the Chutiya word 'Bishu'. 'Bi' means extreme and 'Su' means 'rejoicing' like other Springtime tribal festivals.

The Bihus are the national festivals of Assam. There are three such festivals in Assam: in the months of 'Bohaag' ('Baisakh', the middle of April), 'Maagh' (the middle of January), and 'Kaati' ('Kartik', the middle of October). Each Bihu coincides with a distinctive phase in the farming calendar.

Bohaag Bihu
The "Bohaag Bihu" marks the New Year at the advent of seeding time, the "Kaati Bihu" marks the completion of sowing and transplanting of paddies, and the "Maagh Bihu" marks the end of the harvesting period. Bohaag Bihu is also called the "Rangali Bihu" or the Festival of Merriment, Magh Bihu is also called "Bhogali Bihu" or the Festival of Food, and Kaati Bihu is also called "Kongaali Bihu" or the Festival of the Poor.

Magh Bihu or Bhogali Bihu
Magh Bihu is also known as Bhogali Bihu, derived from the word Bhoga meaning eating or enjoyment. Harvesting is over at this time and the people look forward to the coming days without want. It is a harvest festival. On the eve of Bihu day, called "Uruka", i.e. last day of "Puh" ('Pausa') month, women get busy preparing rice cakes and other refreshments.

Kati Bihu or Kangali Bihu
Kati Bihu is also called Kangali Bihu (Poor Bihu). At this time paddy seedlings begin to grow. In the evenings, offerings are made to the 'Tulsi' plant in the courtyard. Little earthen lamps ('Diyas') are lighted at the feet of the Tulsi plant. Puja's are offered to God for improved yield of crops. The significance of this Bihu is more in the villages, where farmers go to their respective fields and light "Akash-Banti" or 'sky-lamp' hanging from a tall bamboo, to ward off pests and other insects.