In fact, this system of Kashmir Shaivism is based upon Tantras revealed by Lord Shiva. These Tantras are divided into three classes.One class is that of the monistic Tantras. They are called #BhairavaTantras.The second class of Tantras is founded on the mono-dualistic aspect of Kashmir #Shaivism. These Tantras are called Rudra Tantras.
The third class is based on dualistic Shaivism. These Tantras are called Shiva Tantras.
The philosophy of these Tantras was re-originated at the beginning of Kaliyuga by the sage Durvasa. Many centuries later this Tantric philosophy of Kashmir Shaivism was taught by four great Masters in four great Schools Pratyabhijna School, Krama School, Kula School and Spanda School.
Pratyabhijna means recognition. The realization of what one has always been in one’s essential timeless nature. This system was expounded in Kashmir by Somananda.
The Krama School is grounded in space, time and form. Its purpose is to develop such strength of awareness that one transcends the circle of time, space and form and thus becomes timeless, spaceless and formless. This thought of the Krama School of Shaivism was taught by Sri Erakanatha.
The third School of Kashmir Shaivism called the Kula system. The purpose of this School is to discard individual energy and to enter into blissful energy of the totality. This thought was re-originated and taught by Sumatinatha in Kashmir. .
Spanda means “Vibration” and the system which goes by its name directs the spirant to concentrate on each and every movement in this world. Even the movement of a blade of grass will carry you to God-consciousness. This thought was re-originated and taught by Vasuguptanatha
In fact these four Schools are not separate from each other. All the four carry the Sadhaka to the throne of Universal God-consciousness. (swami lakshman joo, jc chatterji- kashmir shaivism)