Although Karthigai day is observed every month, the most significant Karthigai day falls in the month of Karthikai. Masik Karthigai Vrat purifies the system and curbs incurable ailments. The devotee is blessed with a clear vision in life to achieve protection against the evil and enemies with the blessings of Lord Subrahmanya. On the auspicious day of Masik Karthigai, devotees visit the temple of Lord Subrahmanya to seek his blessings. Pujas and rituals addressed to Lord Muruga can win the blessings of Lord Shiva and Mother Parvati. Hence, the Masik Karthigai Vrat is considered highly efficacious.
Once, Devi Durga waged war against the demon Mahishasura. To atone for the dosh, Goddess Durga performed a strict Vrat procedure and worshipped Lord Shiva. As a result, the Goddess was relieved from all the dosha. The day when she observed the Vrat and performed puja was Karthigai. As per an another legend, Goddess Parvati received the half body of Lord Shiva to reside on the day of Karthigai and hence the day is considered auspicious.
Celebrations and Rituals:
Devotees clean their house and take a sacred bath early in the morning on the day of Masik Karthigai. The puja altar is prepared, and the image of Lord Murugan is installed with a floral garland. A lamp prepared from flour, ghee and jaggery are lit which s considered very auspicious. The puja is performed by chanting of Subrahmanya Kavacham and Kanda Sashti Kavacham. Incense sticks, sandal- turmeric paste, and vermilion are offered to Lord. Devotees prepare several delicacies as a Bhog. Later, Aarti is performed forLord Subrahmanya. Many devotees keep fast on this day.
The fast commences during the dawn and ends during the dusk. Puja is performed in the morning as well as in the evening. The rituals can be observed for six months starting from the Tamil Months of Adi and Thai. Observing the Masik Karthigai Vrat for 12 consecutive years is said to bestow the devotees with the great fortune and blessings of Lord Subrahmanyam. Karthigai Vrat consists of total abstinence from food, and if a strict Vrat is not possible, the devotee can consume fruits and milk.