Drupchen (Tib. གྲུབ་ཆེན་, Wyl. sgrub chen) - literally "vast accomplishment," is a form of intensive group practice that epitomizes the depth, power, and precision of the Vajrayana, drawing together the entire range of its skilful methods-mystical, ritual, and artistic-and including: the creation of the mandala house; the complete sadhana practice with visualization, mudra, chant, and music; continuous day and night practice of mantra; the creation of tormas and offerings, with sacred substances and precious relics; the tsok feast; the sacred dance of cham; as well as the construction of the sand mandala. All blend to create the transcendent environment of the pure realm of the deity and awaken, for all those taking part, the pure perception of this world as a sacred realm.
So it is said that several days participating in a drupchen can yield the same results as years of solitary retreat, and great contemporary masters such as Kyabjé Dilgo Khyentse Rinpoche have made a point of encouraging and reviving the practice of drupchen, because of its power of transformation in this degenerate age.
The meaning of drupchen is to purify, to tame our body, speech and mind in order to become authentic and beneficial says Patrul Rinpoche.
Dzongsar Khyentse Rinpoche says: "A drubpa chenpo, a drupchen, requires all kinds of details. For example, you have to do six sessions, you must have a certain number of yogis and yoginis and the sound of the mantra must never be interrupted. If there's any drupchen happening, one must try to participate. Just as we should participate in tsok offerings again and again, it is really good to participate in a drupchen as a Vajrayana practitioner again and again. It is believed that just going to one drupchen will take care of all samaya breakages instantly. Where there is no drupchen, one should try to organize one. "