The new year of Assamese calendar usually falls on April 15. The new year starts with the month 'Bohag'. This is the reason why Rongali Bihu is also called 'Bohag Bihu'. The word 'Rongali' is derived from 'Rong' which means Happiness and celebrations. So this festival represent happiness of the society. All the three Bihu festivals of Assam are related to harvesting. Rongali bihu falls in a period when the there is no work for the cultivators but still there is enough in the store to enjoy. Being a agriculture based state, Assam, has always marked this Bihu as the symbol of joy. This also biggest the festival in Assam and celebrated in every corner of the state.
On the eve of the Bihu the womenfolk clean the clothes and prepare special Bihu delicacies like 'Chira', Pitha, etc. In the rural areas the men folk remain busy in collecting necessary items such as 'Tara Pogha' (ropes for the cattle) prepared out of slices of 'Tara' - (an indigenous creeper) and vegetables such as raw turmeric, brinjal, gourd etc for the next days 'Garu Bihu'.
The first day of the Bihu is dedicated to the cattle (Goru), as cows and bullocks provide them with means of livelihood. On this day, early in the morning the cows and bullocks are ceremonially bathed in a river and ponds. Their feet are washed; horns and hoofs are painted various colours and are adorned with flower garlands. Cut pieces of the vegetables like brinjal, gourd etc. are offered to them. Their old ropes are cut and they are let loose for the day. On this day, they are permitted to pasture in any field without restraint. On returning from the river verybody takes a special bath and the younger people seek the blessings of their elders. In the evening, when the cows return home, they are tied with new ropes (Pogha) and are entertained with cakes especially prepared for them. Some people also light oil lamps and incense in the cowsheds to ward off mosquitoes and illness.
On the next day, called Manuh Bihu, special dishes made of flattened rice, curds, and jaggery and sweets are prepared and eaten. On this day 'Bihu Husori' is formally inaugurated at the Namghar (Prayer hall).
The third day is called Gosain Bihu and is dedicated to the worship of deities.
On all three days of the festival, troupes of musicians and dancers visit houses and perform the Bihu dance in the open. The young boys and girls wear new clothes on this day and after enjoying the special preparations of the Bihu, spend the time in egg fight ('Koni Juj'), singing songs of love and romance. Such gatherings are called "Mukoli Bihus" (Open Bihus). The songs are very popular among all sections of the people. The folk songs associated with the Bohaag Bihu are called "Bihu Geets" or Bihu songs. Young men and women perform bihu dances and sing to the accompaniment of drums and pepa, a flute made of buffalo horns. Fairs are organized at different places and the mood of festivity is present everywhere. Where available the girls decorate their long hair with Ko-pou flowers.
Husori : Village elders move from household to households singing carols, also in the style of bihu geets, called husoris. It possibly derives from the Dimasa Kachari word formation ha (land) and char (move over): hachari. Villages could have more than one Husori band, and they would visit households in a village non-contiguous to itself, first singing carols at the Naamghar. The husari singers then visit individual households, by first announcing their arrival at the gate (podulimukh) with drum beats. The singers are traditionally welcomed into the courtyard where they sing the husori songs and perform a ring dance. At the end of the performance they are thanked with an offering of tamul in a xorai, whereupon the singers bless the household for the coming year. If there is a bereavement in the family, or the family does not invite the husori singers due to an illness, the husori band offers blessings from podulimukh and move on. Generally the singers are all male.
Mukoli Bihu : Young unmarried men and women attired in traditional golden silk muga dance the bihu and sing bihu songs in the open fields. The songs have themes of romance and sexual love, requited or unrequited. Sometimes the songs describe tragic events too, but treated very lightly. The dance celebrates female sexuality.
Jeng Bihu : This is Bihu dance and song performed and watched only by women. The name "jeng" comes from the fact that in earlier days women in the villages used to surround the place of their performance with sticks dug into the ground called jeng in Assamese.
Rongali bihu reflects the rich culture of Assamese society. Bihu songs involve various indegenous Assamese musical instruments like pepa, gogona, dhol, toka, taal, hutuli, etc. The Bihu dance is related to rich colourful attire of the Assamese culture. This Bohag Bihu also involves various delicious Assamese recipes.
When it comes to Assamese culture and society the first thing that comes to any one inside or outside of Assam is nothing but Bihu, to be more specific, Rongali(Bohag) Bihu.
In the cities due to the pressure of of modern day life the modes of Bihu celebrations have changed to a great extent. Mukoli Bihus are not common any more. In towns and cities, there are well-organized Clubs, Bihu committees and Associations which organises Bihu festivals where professional and amateur groups perform. Various contests are also organized where young men and women compete in Bihu dancing and the best dancer of each category is awarded the title. But, in most of the rural areas its originality and emotions of Bihu are very much alive.