After Upanayanam, study of Vedas commences on the first Aavani Avittam day. Utsarjana karma is done in the following Pushya (Thai) month, study of Vedas is halted and in the next six months, as much as possible of the six Vedangas, viz. Siksha, Vyakarana, Chandas, Niruktam, Jyotisham and Kalpasutram is studied. Then in the Sraavana month of the following year, on the day of Upakarma, Upakarma is performed and study of Veda mantras is commenced again. This karma of starting study of Vedas is known as Upakarma. Only if Upakarma is performed in this manner, will the meagre store of Veda mantra with us have power. If not, it will become ‘yatayama’ like the food described in Bhagavadgita.