By Swami Harshananda
A Somayāga has an introductory or opening rite called Prāyaṇīyā and a closing rite called Udayanīyā. These sacrifices belong to the iṣṭi type.The Prāyaṇīyā is performed after the dīkṣā day. Going out to fetch the soma creepers is the most important part of this rite. Offering of caru and ājya to some deities is also done in this ritual. In the Udayanīyā iṣṭi, the concluding rite is performed in the fire of the shed called prācinavanśa. It is erected with bamboos and has four oblations.
- The Concise Encyclopedia of Hinduism, Swami Harshananda, Ram Krishna Math, Bangalore