According to the western calendar today marks the 50th anniversary of the passing of one the greatest masters of early 20th century Tibetan Buddhism, Jamyang Khyentse Chökyi Lodrö. He entered into his final meditation (thug dam) in the palace temple in Gangtok, which had been his home since coming into exile from Tibet in 1956. His death was kept a secret until his final passing into parinirvana three days later, when suddenly an incandescent light illuminated the sky over Gangtok, hours after nightfall.
Sogyal Rinpoche, using the examples of the Sixteenth Gyalwang Karmapa and Kalu Rinpoche in The Tibetan Book of Living and Dying, describes the death of a master:
"A realized practitioner continues to abide by the recognition of the nature of mind at the moment of death, and awakens into the Ground Luminosity when it manifests. He or she may even remain in that state for a number of days. Some practitioners and masters die sitting upright in meditation posture, and others in the "posture of the sleeping lion." Besides their perfect poise, there will be other signs that show they are resting in the state of the Ground Luminosity: There is still a certain color and glow in their face, the nose does not sink inward, the skin remains soft and flexible, the body does not become stiff, the eyes are said to keep a soft and compassionate glow, and there is still a warmth at the heart. Great care is taken that the master's body is not touched, and silence is maintained until he or she has arisen from this state of meditation."