Upakarma is regarded as the one of the most important karmas for a Brahmin
. Upakarma means beginning (‘arambham’); it marks the beginning of the study of the Vedas
(Veda Adhyayanam). In Tamil, the Vedic ritual of Upakarma is also known as Avani Avittam. Every year on Aavani Avittam, the Poonal
(sacred thread) is changed anew, along with the chanting of mantras.
According to Hindu scriptures, every year, learning of Vedas is done for a period of 6 months, which ends on Pushya Pournami (Thai Pournami). This temporary stoppage of Veda learning is known as 'Adhyaya Utsarjana'. The students learn Shastras for the next 6 months.
Again, the Veda studies are taken up in the Shravan month (Avani). This restarting is a karma, which is performed as Upakarma. The main part of Upakarma is the Veda Arambha that the Sastrigal/Vadhyar (teacher) performs after changing of Upaveetham (Poonal).