The process of yajna is highly efficacious to influence the physical world by producing the vibrations in the subtle realm. The science behind this efficacy is quite deep and wide. What is the purpose? What kinds of vibrations are to be generated to accomplish this purpose? Depending on these requirements, the type of yajna, the design of havan kunda (pit for preserving fire), and the karmakanda (rituals) are decided. That is why, the experts of yajna (the great sages) discovered, after a considerable research effort in this direction, the various methods/modes of yajna and several types of karmakanda. To explain these processes fully will require several volumes. In this article an humble attempt has been made to give only a glimpse.

(1)Smartagni- The opinion of experts (of yajna) is that Agni (fire) should be established, according to the prescribed method, in the home after marriage. This is called Smartagni. Oblations are offered in this fire daily in the morning and afternoon.

(2)Shraut-karma- Establishment of Garhapatya, Ahvaniya and Dakshinagni, in accordance with the rituals, is called Shrautadhana. The yajnas that are performed in these fires are called Shraut-karma.

(3) Darsha and Paurnamasa yajnas - The yajnas that are performed on no-moon day and full-moon day are called Darsha and Paurnamasa yajnas respectively.

(4) Chaturmasya yajna - There are four ‘parva’(s) (festivals) of this yajna which are performed with an interval of four months. They are, first, Vaishvadev parva on the full- moon day of the month of Phalguna; second, Varuna pradhasa parva on the fullmoon day of the month of AshaÃa; third, Sakmedha parva on the full- moon day of the month of Kartika; and fourth, Shutasiriya parva on the new moon day of next Phalguna.

(5) Nirudh Pashu-Bandha Yajna- The yajna that is performed every year in the rainy season or on the Sankranti days of summer and winter solstices is called "Nirudh Pashu-Bandha".