The Sacred Tooth Relic as Rain-Maker
If the sacred bodhi tree could cause rain because it has been once in contact with the Buddha himself, then, relics of his own body certainly have more power than the bodhi tree to produce rain. The most important of the corporeal relics of the Buddha that serves this function even today is the Dalada, the sacred Tooth, which is enshrined in a golden casket at the Dalada Maligava, The Palace of the Sacred Tooth at Kandy.
The left eye-tooth relic of the Buddha was brought from Kalinga in India to the island in the fourth century AD, about six centuries after the arrival of the bodhi tree. The king who ruled the island at that time was Sri Megha varna (303-351 AD) His name denotes, rather coincidentally, ‘the Resplendent one whose complexion is that of the Rain-cloud'.
The king and the people were still aware of the rain-making power of this relic. It is recorded that the prince and the princess who brought this relic to the island first took shelter at the Megha Vihara (Temple of the Rain-cloud) where Parjanya, the Rain god, was propitiated. In the course of time the Tooth relic began to acquire prominence over the bodhi tree at Anuradhapura because unlike the tree the tooth relic could be removed from its original site when necessary.
The rain-making power of the sacred Tooth soon made it the national palladium of Sinhalese kingship. For the belief had taken root among the royalty and the people that whoever possesses the sacred Tooth had the legitimate right to rule the land. It was noted earlier that the ideal king is one who has the power to cause rain in due season and thereby bring prosperity to his kingdom. The possession of the Tooth relic thus gave the king the power that he needed to remain the legitimate sovereign. The king who was in possession of the Tooth relic thus had a better claim than others to rule this land. So the story of the Tooth relic in Sri Lanka is, in fact, the story of innumerable kings and princes, local and foreign, and of innumerable monks and men who struggled to keep possession of this treasure and keep it from falling into hostile hands.
"The overarching of Sinhala state and religion" writes Amunugama, "was typified by the king's possession of the Tooth relic. He who had the relic was King. In the last days of the Sinhala monarchy there were many pretenders to the throne. Their first act, to secure legitimacy, was to attempt to capture the Tooth relic" (1.29)
Today the Tooth relic is housed in Kandy because it was the last seat of the Sinhalese kingdom. "Till the fall of the Kandyan kingdom in 1815 the Dalada remained as strong a symbol of sovereign; is ever. Safeguarding the Dalada against European powers was of prime importance. In 1611 when the Portuguese approached Kandy, the King (Senarath) quickly hid the Dalada in a safe place not too far from Kandy, and brought it back to Kandy when they retreated. The Europeans themselves were quick to realise the political importance of the Dalada, and its capture became a prime objective of theirs. When in the rebellion of 1818 the British captured the Dalada, the people gave up resistance, acceding that since they have the Dalada they are indeed the masters of the country" (29.18-19)
This also explains why the Sacred Tooth is housed in a māligāva, (royal palace) rather than in a temple (vihāra,) Even the British governor was referred to as the ‘king' and his residence, the raja-gedara, the King's House.
The lay custodian of the Sacred Tooth in Kandy today is known as the Diya Vadana Nilame, literally, the Water-increasing-official. He is, in other words, the Water-increaser or Rain-producer. "Thus the Diyavadana Nilame was the minister who was responsible to see that the people had rain in due season to sow their fields and cultivate their crops, and that was the reason why this particular minister was entrusted with the custodianship of the instrument of rain making of the Buddhist kings of Ceylon." (14.114)
History records many festivals in honour of the sacred Tooth. One of the earliest references was that of the Chinese pilgrim, Fa Hien, who visited this land in the fifth century AD. According to the eye-witness account of Fa Hien this relic was brought forth in the middle of the third month and was carried in procession along the roads to Abhayagiri vihara in Anuradhapura. Godakumbura explains the significance of this timing thus "If the Buddhist year began with Wesak (May-June), the third month would have been Aesala (July August) in the dry season at Anuradhapura. The sacred Tooth was taken to the Abhayagiri vihara to a hall of the Buddha there. The festival of the Tooth relic was also instituted for the purpose of obtaining rains"( 14.108)
The Sinhala chronicle ‘Dāladā Siritā, (Rituals of the Sacred Tooth) written in the fourteenth century, enumerates the rules and regulations pertaining to the maintenance of the sacred relic, and according to it. Tooth relic festivals should be performed annually to obtain rain.
Hieun Tsiang, another Chinese traveler who visited the island in the seventh century provides us with information that has specific relevance to its magic. "The king three times a day washes the Tooth of the Buddha with perfumed powdered water, sometimes with perfumes. Whether washing or burning, the whole ceremony is attended with a service of the most precious jewels" (26.281)
The annual procession in Kandy held today may be viewed as an amalgamation of two separate but interrelated processions the Dāladā perahaera and the Aesala perahaera.
Thus the procession at Kandy is sometimes called the Aesala Perahaera, and sometimes the Dalada perahaera, and is considered the most colourful of the Buddhist festivals in Sri Lanka. ‘The Asala festival is not only the largest festival of the Temple; it is also the largest festival in Buddhist Ceylon, and is perhaps one of the largest ever held in the Buddhist world. Each year about 200,000 people participate as observers. The people who perform functions in it and directly related to it number over one thousand. It is also a large festival in terms of duration it now lasts twenty-one days and in Kandyan times it lasted longer" (29.70)
From Water in Culture: The Sri Lankan Heritage by J.B. Disanayaka (Colombo: Ministry of Environment & Parliamentary Affairs, 1992) pp. 61-63