Buddha Jayanti in Bhutia language is called Saga Dawa.
What is it?
Prince Siddhartha Gautam, who was born in the forest of Lumbini in the district of Rupendi in Nepal (about 563 years before the birth of Jesus Christ), later on became lord Gautam Buddha after achieving enlightenment in 526BC and became the spiritual leader of Buddhist religion. Saga Dawa is the festival celebrated to commemorate the birth anniversary of this great spiritual leader. It is the most pious day for Buddhists. Buddhists attend monasteries or ‘chaityas’ and recite prayers.
All Buddhist of Sikkim assemble at sacred and ancient gumpas like Pemayangchi, Tashiding in national dress and offer items like water, incense sticks and puja to different deities along with lord Buddha and than they lake out a religious procession around gumpas carrying sacred scriptures on their heads and chanting a typical Buddhist mantra while turning a prayer wheel with one hand.
When is it?
According to Hindu Calendar this festival falls on Baishaki Purnima, the full moon day, in the month of April-May. In 2016 this is 21st May. It is a Government holiday (although not much of a holiday on a Saturday!).
The day on which Siddhartha renounced the world and took to hermitage falls on a Baishaki Purnima and is called Mahavinishkraman. Co-incidentally the birth, enlightenment and the death of Gautam Buddha all fall on the same day of Baishaki Purnima, that is why, the festival of Saga Dawa is highly revered by Buddhist.
Prince Siddhartha Gautam had to mourn the death of his mother immediately after he was born. He was put to the care of a step mother who also died a premature death after few years. King Suddhadhan (or Shuddhodana) the father of Prince Siddhartha Gautam, was the King of Kapilavastu. From an early age Prince Siddhartha Gautam developed aversion for materialistic world and showed an inclination towards the life of a recluse which finally resulted in this vehement disapproved of the luxury and pompous court life of his father.
While on a stroll (or riding in a chariot – sources differ on the details) he chanced to see diseased, aged and poor people suffering which set him contemplating as to why people have to suffer on this earth. His depressed mind reached its height when he saw a dead man. Being unable to answer himself the reason of a man’s birth, his old age and, finally, his death on earth, Siddhartha left behind his wife Yoshodhara, only son Rahul and the luxurious court life of his father in quest for true explanation of life.
Siddhartha could not get a satisfactory explanation from his associations with pandits and Sadu-Santas; his thirst for truth remained unquenched. So he left them behind and finally came to Gaya (or Bodhgaya) a province in Bihar, and started meditating under a pipal or Bodhi tree till he achieved enlightenment on the full moon day of Baisakh and became a Buddha. His faithful servant Channa taught him that everybody on the earth was fated to pass through the first three stages in their lifetime.
Today, the religion Buddha preached is known as Buddhism, his philosophy as Boudha Philosophy and the place where he achieved enlightenment as Boudhgaya. Buddhism, after spreading in India and Nepal spread to countries like Sri Lanka, Burma, Thailand, Laos, Cambodia and Vietnam and in the North Eastern countries like Tibet, Bhutan, China, Mongolia, Korea and Japan.