Pātaka (sin) and prāyaścitta (expi-ation of sin) are two of the widely discussed topics in the smṛtis and dharmaśāstras. Sins may be serious (mahāpātakas) or minor (upapātakas). The prāyaścittas prescribed for the mahāpātakas like killing a brāhmaṇa or incest, often end in the death of the sinner. But, those prescribed for the upapātakas like minor thefts or abandoning the Vedic fires, are tolerable and purify the sinners.
Kṛcchra is a very general name given to most of these prāyaścittas. Bālakṛcchra—also called śiśukṛcchra or laghukṛcchra—is one variety prescribed for upapātakas in which the expiation is light and easy. If kṛcchras are usually spread over 12 days, bālakṛcchra is observed only for 4 days. It consists in eating once only in day time on the first day, once only in the night on the second day, eating food that comes unasked, that too only once, on the third day and, fasting on the fourth day. Other general rules as applicable to kṛcchras like bathing thrice daily, speaking the truth and so on, should also be followed.