Bratabandhan (Sanskrit brata-promise,bandhan-to be bound), Chudakarma or simply bratabhanda is an ancient Hindu tradition carried out in Hindu families. This tradition is based on the four age periods of a Hindu man, namely Bramhacharya(0-25 years), Grihastha(25-50), Sanyasa (50-75) and Banaprasta(75+).
A religious ceremony is held where a boy shaves his head and performs various rituals. It is a symbolic representation that a boy is mature enough to perform his duties as a bharmachari(that is to learn).
Traditionally these boys were then sent to ashrams of gurus to learn in a vedic system of education. However today it is only represented symbolically by letting the boys beg(the ancient shyshas in ashrams used to beg home to home). At this point, the boys who want to renounce family life and get to the gurus by running (though it is just pretended as doing so)is avoided by the mama (maternal uncle) who lures them to material world or grihastha by offering money. These boys promise to stay home and at the same time perform the karmas of a bramhacharya (studying, earning a living and performing religious rites). Thus after this ceremony the boys are considered men (though not physically). They are given the Janai (yagyopavita-the holy thread from yagya)and are expected to keep with the rules and norms of full-aged men. This promise, taken by wearing the janai, holds them in a bind. This gives its name bratabhandha. From this point onwards they are permitted to take an active part in religious ceremonies (pujas, last rituals, marriages, etc.).