The Dzogchen teachings are considered the pinnacle of
Buddhist meditation practices, and often the practices are centered
around working directly with the nature of the five elements. The
five element practices that Nyala Pema Dudul revealed as
terma was called "Sky-Encompassing Self-Liberation"
(Kha'-Khyab Rang-Drol in Tibetan), and within that series
of teachings there is a practice of alchemy called "Chulen of
the Three Dimensions." The picture below is of the cave where
he revealed this terma.
Chulen literally means "taking the
substance." There are many types of chulen that have various
applications. Tsi dang contains eight ingredients which
work together to strengthen and coordinate the function of the
major organs. Its main effect is physical health and youthfulness.
Another type of chulen is called rotsa, which is used
specifically to strengthen and balance energy; so there are many
different kinds of chulen traditions and medicines.
In the contemplation tradition of chulen, the pills are used in
conjunction with meditations and yoga in order to recognize
awareness as the pure nature of the elements. The practice is a
gradual process where the practitioner weans himself from eating
solid food, and attainment of the practice is the development of
the ability to subsist on the pure essence of the elements
themselves. At that point, the practitioner no longer has to eat
anything.
The teaching instructs the practitioner on the preparation of
medicinal pills, and the method of visualization, breathing and
yogic techniques to reintegrate the practitioner's inner and outer
experience of the elements back into its natural state. As Namkhai
Norbu writes, "Chu is the essential substance of the
elements: it maintains the physical body and, if our energy is
uncoordinated, it co-ordinates it, if it is weak, it reinforces it.
Therefore, chudlen is useful, above all, to harmonize
energy and develop clarity...The Body of Light (Jalu) can
manifest when the principles of Dzogchen are combined with
Chulen." The terma text itself mentions that when
the great saint Yeshe Tsogyal asked Guru Padmasambhava for these
teachings, he replied, "Listen. There are many methods to achieve
total realization, but in particular, there is the Chulen
of the Three Dimensions, which embodies infinite qualifications."
In Drubje Pema Dudul's biography, it is said that
he practiced Chulen with a little solid food for the first
three years, Chulen of medicinal pills for the next three
years, and Chulen of absorbing the essence of the elements
directly from space for the final three years of his retreat. At
the conclusion of his nine year retreat he had attained full
enlightenment as his teacher the Mahasiddha Choying
Rangdrol had predicted.
When Drubje Pema Dudul knew his time was near, he called all of his
students back to the area where he lived, and after giving them
each his heart advice and practicing the Feast Offering with them,
he had them follow him up a mountain, where he set up a small tent
and asked them to sew the door shut. With the instructions that
they should practice the Feast Offering together for a week before
checking on him, they witnessed numerous rainbows appear over the
mountain and the surrounding area. When they returned to the spot
where his tent stood, they found it still sewn shut; opening it,
they found his body had disappeared. His meditation belt and cloak
were in a heap, within which they found all of his hair and twenty
nails from his hands and feet. This picture is of the shrine built
over the spot where he manifested the Rainbow Body.
Drubje Pema Dudul's lineage continues through many masters,
including Chogyal Namkhai Norbu, Wangdor Rinpoche, as well as Tulku
Serdo Rinpoche, Khandro Sherab Lhamo, and Lama Pema
Karma.
Read more at :
http://www.tealchemy.org/what/alchemists/index.html