A brief introduction
Sōma Yāga is very important and difficult task among Yagyās. The main oblation (offering) is the Juice of Sōma latha plant. That is why this Yagnya or Yāga is called as Sōma Yāga. There are mainly four kinds of Sōma Yāga whose names are Ēkāha (एकाह), Ahiēna (अहीन), Sādhyaskra (साद्यस्क्र) and Sathra (सत्र). All Sōma Yāgās are Shroutha Yagnyās. Athirāthram is one of the Sōma Yāga’s called Ahiēna and is conducted continuously for 12 days (some nights also). Since it is a Shroutha Yagnya it requires specialists to do the Yagnya. For this Yagnya Sōma Juice is squeezed from the Sōma latha plant. These plants are rare and are divine gifts given to humans. These plants cannot be located everywhere. Only those who conduct Sōma Yāga know the location of availability of these plants. It is very difficult to identify these plants. Once identified, the process of obtaining the Juice from these plants becomes another skilled work. The construction of the Yagnya Shāla is another big task because it involves a lot of measurements and material details. More than 25 Rithviks are required for this Yāga and the preparations will take a year or so. Every material used for this purpose is collected and made by crafts men from India and have to be transported from India.
Ēkāha: The Sōma Yāga which is fulfilled in one day excluding other activities (which take about four more days) is called Ēkāha. There are seven branches or endings for Ēkāha Sōma Yāga and are called Agnistoma (अग्निष्टोम), Ukthya (उक्थ्य), Shodashi (षोडशी), Athirāthra (अतिरात्र), Athyagnistoma (अत्यग्निष्टोम ), Vājapēya (वाजपेय), and Apthoryama (अप्थोर्यामा).
The Sāma in which Agni is praised is called as Agnistoma. Sōma Yāga which ends with the help of Agnistoma is called as Agnistoma branch. In a similar manner the Sōma Yāga which ends with the Ukthya Sāma belongs to Ukthya branch. The first four branches Agnistoma, Ukthya, Shodashi and Athirāthra are collectively called as Jyothistoma branch because in all these four Sōma Yāgās Praise of Jyothi is done. The Stōmās (Praising) Trivruth, Panchadasha, Sapthadasha, and Ēkavimsha are called Jyothi and are used in Agnistoma, Ukthya, Shodashi and Athirāthra.
Ahiēna: The Sōma Yāga which is done from 2 to 11 days is called Ahiēna. Athirāthram or Agnichayana is considered in Ahiēna if the Ahiēna goes on the 11th night and completes on the 12th day.
Sathra: The Sōma Yāga which is done from 13 days to Thousands of years is called Sathra.
Sādhyaskra: The Sōma Yāga that is done only in one day including all activities is called Sādhyaskra.
