Sabarimala sits on a forested hill in Pathanamthitta district, Kerala, inside the Periyar Tiger Reserve, 1,260 metres above the sea and ringed by eighteen hills. There is no road to the shrine. The last stretch is walked — from Pamba up Neelimala, or, on the older and harder route, from Erumeli through the forest by way of Karimala.

The deity is Ayyappan, also called Dharma Sastha, worshipped here as a naishtika brahmachari — a lifelong celibate ascetic, seated in the yogic posture with a band tied around his raised knee. The shrine has long been open to pilgrims of every caste and faith, and pilgrims on the Erumeli route stop at the mosque of Vavar, Ayyappan's companion in the temple's legends, before going on.

The climb begins forty-one days before the hill. The pilgrim takes the mala, wears black or deep blue, goes barefoot, sleeps on the floor, eats simply, speaks carefully and keeps celibacy. The point of the vratham is not endurance for its own sake — it is to arrive at the foot of the steps already lighter than one came.

On the head rides the irumudikettu, a cloth bundle with two compartments. The front holds the offerings for the deity, above all a coconut filled with ghee. The back holds what the pilgrim needs for the road. At the sanctum the ghee is poured over the idol as neyyabhishekam and the emptied shell is given to the fire — the vessel broken once what it carried has been handed over.

Nobody climbs the eighteen steps without that bundle. It is the one rule that has never softened.

The most widely taught reading divides the steps into four groups: the five senses that lead the mind outward; the eight passions that keep it agitated; the three gunas — including sattva, because even clarity is a rope, and the Gita's fourteenth chapter asks the seeker to pass beyond all three; and finally knowledge and its absence, because learning is a possession too, and possessions do not go through the door.

Other counts are held just as sincerely — the eighteen puranas, the eighteen chapters of the Gita, the eighteen hills, the eighteen tatvas or weapons of Ayyappan, the eighteen hill deities honoured in the padi pooja. Sources differ on the order within the groups as well: some place avidya before vidya, some list tamas before rajas. This page follows the common five–eight–three–two arrangement, which is one reading among several rather than a single authority.

At the top of the eighteenth step is the sentence the whole climb was for. Tat Tvam Asi — That Thou Art — the Chandogya Upanishad's great saying, inscribed at the shrine. Whatever the pilgrim set down on the way up turns out to have been the only thing standing between the two.