YAGNA AND AGNIHOTRA
Yagna is also known as Havan. Yagna is very complex subject and a person has to study it on its own.

Each Yagna creates a mandala, and each mandala invokes a specific cosmic energy. The rituals performed in Rikhia were magnetic movements or mudras. They were abhinaya, gestures to guide the macrocosmic prana shakti into the microcosmic mandala that had been created.

A Yagna has four basic parts. In the first part, an inert mandala is created which is without life or prana shakti, the creation of the form. In the second part, the image or form is infused with prana shakti, the prana pratishtha. The third part is upachar, intensification and magnification of the energy that has been invoked. The fourth part is parayan or prasthan, the release of energy, the culmination of the Yagna. These are the different components of any Yagna.

The word Yagna comes from the root yaj, meaning 'to offer'. It implies the offering of all things that are pious and auspicious, which nurture and sustain life and creation. This offering is made to the cosmic, universal, global energies and the shakti in order to sanctify the elements – earth, water, fire, air and ether. The offering is made to charge the elements with nutrients, thus increasing the healing properties of the elements.

Mantras are words of power which create a specific vibration in the environment. Mantras purify the environment. The concept of mantra exists in many mystic traditions, which in the past have used mantras to aid the function of the elements, to control the elements, to harness them for the betterment of society, the planet and creation. Nowadays, the mantras that we recognize are those that give control over the natural processes, with the strength to manipulate events. Therefore, mantras may seem like magical spells, witchcraft and wizardry, but in reality they have a different function to perform.

Yagna is the creation of a mandala, the cosmic image or symbol, at one point in time, at one location in time, and it realigns all the cosmic magnetic energy fields in the universe. There are different kinds of Yagnas. Some Yagnas are performed for the betterment of the human being. Some are done to assist the cosmic forces. Others are to heal the elements. Others provide material gains and benefits. In the past, Yagnas were conducted to bring about a birth; for example, the births of Rama and his brothers, and of Draupadi and Dhristadyumna, occurred as a result of Yagnas. When a Yagna is performed correctly, it becomes a very powerful instrument for bringing about a change. Therefore, Yagnas should be performed wisely.