The Hindu festival going by the Kartikai is celebrated on the full moon day in the month of the same name corresponding to the English months of October- November, when the moon is in conjunction with the asterism Kritikai (Pleiades.)
Though the observance of the Vratam is to propitiate the five elements, greater importance is attached to the propitiation of Agni (fire) and all the houses are profusely lighted and illuminated after Sunset, in consequence.
The reason why fire is given prominence over the other elements is furnished in the allegorical and deeply spiritual myth in, which Lord Siva, one of the Hindu Trinity, is said to have appeared in the form of a pillar of fire to teach the creative and preservative aspects, Brahma and Vishnu, the knowledge of infinity, beyond time, space and limit, on this particular occasion.
Brahma is said to have assumed the form of a swan and flown upwards to, find the top of the pillar, while Vishnu took the form of a boar to dig down and reach its bottom. The flag staff or dhwaja-stambha in temples, is intended to symbolize this pillar of fire. The Indian yogis (sages) say that the pillar of fire is nothing but the halo of brilliant light surrounding and interpenetrating the spinal chord within the spinal column in man.
The peculiar custom of burning heaps of dry leaves, twigs, etc., going by the name of chokkappanai in front of temples deserves its rational explanation. The custom apperars originated from the incidents recorded in the myth wherein Siva is said to have burnt the chariots of certain asuras who were harassing the sages and others on this earth, at a particular period. The chokkappanai (the collection of dry leaves, twigs, etc.) is symbolical of the aerial vehicles of the asuras, burnt by the fire emanating from the third eye of Siva.
There are a number of myths emphasizing the importance of the observance of this Vrata. King Bali is said to have observed this Vrata to get rid of a burning sensation all over his body and the goddess Parvati herself is said to have observed it to be freed from certain sins she had committed, to wit, the breaking of a Sivalingam unwittingly, while engaged in single combat with the asura Mahishasura whom she slew.
A preparation of fried rice is considered specially acceptable to lord Siva, and, the custom appears to have originated from the incident narrated in the Maha Bali myth, quoted above. Ball is said to have offered this preparation to Siva to be freed from the burning sensation he felt in every cell of his bodily tissues, so to say.
The material, fried rice, is perhaps meant to symbolise the condition of the cells in the body of Ball that were being fried and consumed by the invisible fire. Its offering is intended to convey to Siva the condition of the cells in his body and thus silently to beg for his mercy. Further, Bali perhaps thought that fried rice, when consumed by him, might not build cells causing the burning sensation since they are already subjected to fire by the frying process. Even though the burning sensation might not be altogether removoed by this diet, yet it might perhaps lessen the severity of the feeling, by forming cells incapable of furnishing as much burning matter as cells formed by the cells of cooked rice, raw rice and so on. These customs are symbolical and figurative and consequently, the idea conveyed must be taken in a restricted application of the language whose meaning should not be stretched. Siva represents fire as he is the lord of the burning ground. So anything deprived of humidity and subjected to heat, might naturally be taken by people as an acceptable offering to Siva. Hence, perhaps, arose this custom of offering fried rice to the deity on this occasion.
When temples are located on hills, they are considered to be specially suitable for worship and highly influence- radiating. As the temple at Tiruvannamalai in the South Arcot district is one of such temples dedicated to Siva, this festival is observed there with great eclat and thousands of people flock there every year, to witness the celebration, take part in them and derive the blessings of the presiding deity Arunachaleswara. The whole rock is illuminated and a huge flame of torch is lighted at its top after sunset on this festive day.
The hill consists of three fortified peaks. The isolated Tiruvannamalai peak is covered with jungles and is accessible only on foot. A natural column rises from the top of the hill perpendicularly, which the devotees of Siva hold to be a lingam or phallic symbol. In fact this place is one of the five main Siva centres in India, and, it is the abode of one of the five lingams brought from the highest of the super-physical regions, to wit Kailash, by Sri Sankaracharya. This temple is considered by the devotees of Siva to be as sacred as Srirangam is for the devotees of Vishnu. The other important places for the observance of this Vrata are Tiruchengodu, Palani, Vedaranyam and Tiruchendur.
On the north wall of the central shrine in the Kalahastisvara temple at Kalahasti, there is a record relating to the 12th year of the Chola king, Rajendra Choladeva I (1011-43 A.D.) mentioning a gift of gold for celebrating the festival of Kritika-dipa.
On the west wall of the first prakara of Brihadamba temple at Devikapuram, there is an inscription of the Vijianagara king, Virapratapa Krishnadeva Maharaya dated, Saka 1443 Vikrama, Kartikai, Ekadasi, Monday, corresponding to 9th July 1920, which mentions providing ghee for lamps during the festival of Tirukartigai.