According to the Pishchila Tantra there are two classes of Gurus: the
diksha guru, or "initiating guru” and the
siksha guru,or "instructing master.”
The diksha guru is our beloved eternal spiritual master. It is he who grants us initiation and connects us to our line of disciplic succession. One can be initiated only by one diksha guru.
The siksha guru gives us instructions on specific aspects of religion, such as different rituals and ceremonies, techniques of concentration, prayers and devotional songs, etc. There is no limitation on the number of siksha gurus one can accept. They perform an essential function in our process of spiritual development.
The diksha guru is like our spiritual father, his role is central and there can be only one. However, just as in the educative process of the child, in which an important place is also given to grandparents, aunts and uncles, and teachers, shiksa gurus have a significant role in our spiritual development.