Mahasidha Rahula, also known as Rahula-Gupta, Rahula-Bhadra and Rahula-Guhya-Vajra is an Indian Mahasiddha who was a teacher to both the great Atisha as well as the founder of the Shangpa Kagyu school, Khedrub Khyungpo Naljor. He is also known by the nickname of "the Yogin of the Black Mountain". 

Rahula-Gupta was born into a prestigious family in India in the 10^th Century. In his early childhood he suffered with sickness and tasted sincere aversion and dislike in the nature of samsara. Upon a search for truth he thus entered the path of Buddha-Dharma and quickly became very learned. He had special efficacies in the yogas, tantras and related practices and treatises. He had visions of many divine deities. Gunasagara and Ratnasagara pruned him with precepts which allowed him to attain Siddhis easily.

He attained the state of realized Mahamudra. An awareness holder with control over the length of his life and eventually seeing the direction of the future of Buddhism, he (Rahula-Gupta) flew to Tibet with his newly acquired miraculous wing power and spent seven months with Khyungpo Naljor, transmitting to him many teachings, especially on the Six-armed Mahakala and the Combined Accomplishment of the Four Deities. (Initiation of guru yoga - 6 armed Mahakala, Vajrayogini, Avaloketeshvara & Green Tara. The practice is considered so profound because it includes everything necessary for the swift attainment of liberation and enlightenment.

From the instruction manual by Jamgon Kongtrul: "The contemplative practice of the Lama Vajradhara grants the highest accomplishments in this very life. Speedy attainment of the stages of the path depends upon two factors: dispelling of hindrances and enhancement of contemplative experience. The ultimate method for dispelling outer hindrances is that of the Protector Gōnpo Chagdruk (White Mahakala); for inner ones that of Tara. The very best method for the outer enhancement of loving kindness and compassion is the practice of Avalokiteshvara; for the inner enhancement of bliss and heat we practice Vajrayogini. Thus a single session of this practice covers every stage of the path. One could accomplish this in three months of undistracted practice. Meditation upon this without fail at each dawn session, brings about ordinary and extra-ordinary accomplishments!"

In his instruction manual on Six-armed Mahakala, the previous Kalu Rinpoche mentions in a note: "At the time of approach, accomplishment and application of activities, this practice of the "Combined Accomplishment of the Four Deities" is indispensable. Complete this practice according to its sadhana and commentary, and you will dispel all outer and inner obstacles and receive blessings." It is one of the most important core practices of the Shangpa Kagyu lineage).

Rahula Mahasidha was the only Indian teacher of Khyungpo Naljor's whom he did not meet in India itself but encountered in Tibet. Through his prophetic eyes he could see the rapid growth of Dharma in the land of snow. He reflected on the people in general and witnessed the poverty-stricken Dharma practitioners of Tibet. Even the great potential yogins didn’t have a stock of Tsampa but were living day by day. He mourned for them and went straight to Lord Maitripa. 

 Lord Maitripa (1007-1078) was an Indian Buddhist teacher who studied at both Nalanda and Vikramasila Monasteries. At Nalanda he studied with the famous teacher Naropa, however at Vikramasila during the tenure of Atisha, he was expelled because of his behaviour. After leaving the monastic life he lived and practiced as an ascetic yogi. Once he was residing at a charnel ground not far from central Dorjeden Bodhgaya, Kosabhikshi cemetery (not Silwei-tsal). Meeting with the great Mahasidha Shavaripa, Maitripa took him as a principal teacher and studied the special techniques of Mahamudra. He was looked upon as a greatly accomplished master of the Buddhist Tantric system (Mahasidha) and is most famous for teaching the Mahamudra philosophy and practice to the Tibetan translator Marpa.

Rahula offered his best of belongings with a few shimmery gold coins to Lord Matripa and requested: “People in the land of snow have very little health and wealth, how can they practice the Dharma? Please Lord descend on me an elixir that will swiftly empower the richness and mark the era of a Golden age for the people of the land of snow”. 

From Lord Matripa’s lion speech: “Well, I give to you that one receives common blessings ostensibly while performing un-common commitments. One will also receive the same energy while practising the common tantra of this lineage”. The tantra is called wishful-filling jewel, heap-of-wood lord, sandalwood lord, black uncompromising compassionate one, 6-armed awareness keeper. It protects from fears of before & after life. It is a subduer of humans, Gods & Satans. It promotes fellowship, prosperity & survival. It destroys evil hordes to ashes. It is unstoppable, a bestower of one or the other. 

Rahula answered: “Exactly that master!”

Matripa said: “Once upon a time, Lord Amitabha had witnessed a compassionate one from Potala Hill (who would later be transformed by Amitaba), who only aspired and committed to the vow not to enter Buddhahood until the last sentient being is lifted from the sea of samsara. The compassionate one would turn the day and night into one to fulfil their wishes and liberate one by one. He vowed to Buddha of limitless light that if he fails, his head should be crushed into a thousand pieces and he would never wake up. While working for incalculable years, signs of liberating sentient beings were beginning to become harder. The compassionate one was seeing the population grow, with the product of the gross afflictions such as hate, harm and envy becoming more common. It was easier previously to wash away the subtle level of stains by his prayers. It was never the same. He thus strongly aroused discontentment & resentment and dropped the vow of pursuing the goal. Without any delay his head broke into a thousand pieces. Immediately Buddha of infinite light (Amitabha) shined and softly said “Noble son, it is in-orderly to drop such an enlightening thought, hence you’ve to prompt for greater aspirations than before to cleanse this mishap. Amitabha blessed for him to obtain eleven faces. The compassionate one thought that it was already an unsurpassable inspiration and unattainable to fulfil even one part of it. He then collapsed for seven days. He arose from his coma in the form of Avalokiteshvara with eleven faces. He thought there must be a faster way to liberate these sentient beings going forward in degenerate times, where they are more obstructed and have shorter lifespans; where suffering is the only way out, exhausting the precious gift of life in amassing their needs, only to meet with another distressful moment; Samaya is weak; they are cursed by their own words; and families are dysfunctional. Avaloketeshvara knew this was not going to be ameloriated, so much so that even practitioners could barely liberate themselves from the Bardo. For that cause, something remarkable must occur. A simple wish should suffice to protect beings here and in the Bardo. Fellowship, wealth and survival should be a by-product.  All the calamities for Tantric yogins must disengage permanently from all trace. I must become an invincible lord of majestic power and assist sentient beings on the path. So as great kindness utters the statement, the facial expression turns serious, sending out dark blue HUM rays from the centre of his heart, which shapes into white wisdom Mahakala with 6 arms. Instantly the ground trembled six times. The perfect formation of a precious wish fulfilling powerhouse was activated in witness of Amitabha.

Amitabha, in the midst of incalculable Buddhas said in one voice “Well done noble son for adopting this form in service of all sentient beings. All the Buddhas will send their secret empowerment. You’ll be granted the power of red Bhairava. We will bestow upon you the impeccable power of invincibility. You are a crown deity of peace & increase. All the lesser pantheon will work under your guidance. According to the Tantra those who propitiate you, practice your Sadhana, or even have thoughts of your presence will receive bountiful fortune. As you fervently hope they will be blessed as they recite your mantra”.

While and after one has taken the vow, by practicing the following one shall meet with the Mind/ wisdom deity. One should never neglect offering incense and torma made from raw ingredients, not harm black dogs, and never apply any doubt with ones Guru.