The phurpa, sometimes called a "magic dagger", is a tantric ritual object used to conquer evil spirits and to destroy obstacles. It is utilized in magic rituals by high level tantric practitioners. The word phurpa is used primarily in Central Tibet, while the word phurbu is used more often in Kham, Amdo and Ladakh.
The component phur in the word phurpa is a Tibetan rendering of the Sanskrit word kila, meaning peg or nail. The phurpa is an implement that nails down as well as binds. It was thus by stabbing a phurpa into the earth, and thereby nailing and binding the evil spirits, that Padmasambhava, regarded as the inventor of this implement, consecrated the ground on which the Samye monastery was established in the eighth century.
Whatever the original shape of the Indian kila may have been (none has survived), it seems very likely that in Tibet the form of the phurpa, with its three-sided blade, was suggested by the pegs that were driven into the earth to hold the rope stays of the tent. Due to the essentially nomadic nature of life in ancient Tibet, the tent was an important part of their routine. While traveling it was used by all, the peasants, the traders, the royalty, nobility and even the exalted monks. Indeed, the peg of the tent is the prototype of the phurpa. Its triple blade is really not a dagger but a peg, precisely the kind of peg used to secure tents. The triple blade of the phurpa symbolizes the overcoming or cutting through of the three root poisons of ignorance, desire, and hatred, and also represents control over the three times of past, present and future.
The triangular shape represents the element of fire and symbolizes wrathful activity. The tenacious grip of the makara-head at the top of the blade represents its ferocious activity.
When using the phurpa, the practitioner first meditates, then recites the sadhana of the phurpa, and then invites the deity to enter the phurpa. As he does so, the practitioner visualizes that he is frightening and conquering the evil spirits by placing the evil under the point of the phurpa. Or sometimes the practitioner visualizes throwing the phurpa in order to impale and subdue the spirits. The success will depend on the practitioner's spirituality, concentration, motivation, and his karmic connections with the deity of the phurpa and the evil spirits.