There are 36 Tattvas in Tantras. Out of these 36, the top 5 are above Maya and are called Suddha Tattvas. They are:
- Shiva Tattva
- Shakti Tattva
- Sadashiva / Sadakhya Tattva
- Ishwara Tattva
- Suddha Vidya Tattva
From 6th Maya Tattva starts and from 7th to 11th five Kanchuk are there (Kaala, Niyati, Vidya, Raaga, Kalaa). 12 to 16th are Purusha, Prakriti, Ahamkara, Buddhi, Manas. Remaining 20 Tattvas are: Pancha Jnanedriya, Pancha Karmyendriya, Pancha Tanmatra and Pancha Mahabhutas. The last of the Pancha Mahabhuta is Prithivi Tattva (earth element), hence it is 36th.
Lord Shiva possesses Five Powers which are:
- Chit Shakti (Power of consciousness)
- Aananda Shakti (Power of bliss)
- Ichha Shakti (Power of will)
- Jnana Shakti (Power of knowledge)
- Kriya Shakti (Power of action)
During the expansion of ParamaShiva from 1st (Shiva tattva) to 36th (Prithivi tattva) various states are present. In the first five stages there is predominance of one power of Shiva. Stage in which Chit Shakti is predominant is Shiva Tattva, Aananda Shakti dominant is Shakti Tattva, Ichha Shakti dominant is Sadashiva/Sadakhya Tattva, Jnana Shakti dominant is Ishwara Tattva, Kriya Shakti dominant is Suddha Vidya Tattva. It is explained by Sri Abhinavagupta in Chapter 8 of Tantrasara as:
तत्र परमेश्वरः पञ्चभिः शक्तिभिः निर्भर इत्युक्तम्, स स्वातन्त्रयात् शक्तितांताम् मुख्यतया प्रकटयन् पञ्चधा तिष्ठति । चित्प्रधान्ये शिवतत्त्वम्,आनन्दप्राधान्ये शक्तितत्त्वम्, इच्छाप्राधान्ये सदाशिवतत्त्वम्-इच्छाया हि ज्ञान-क्रिययोः साम्यरूपाभ्युपगमात्मकत्वात्, ज्ञानशक्तिप्राधान्ये ईश्वरतत्त्वम्,
क्रियाशक्तिप्राधान्ये विद्यातत्त्वम् इति । (Tantrasara 8th chapter)
It has already been explained that the Lord's perfection consists in him possessing five powers (Pancha Shakti). While the Lord is manifesting any [one] of his individual Shaktis, his principal Shakti remains shining in five different ways. When the power of consciousness (Chit) becomes predominant, it is called Shiva Tattva. Similarly, when the power of bliss (Aananda Shakti) becomes predominant, this is known as the Shakti Tattva. When. on the other hand, the power of will (Ichha Shakti) becomes predominant, this is the Sadashiva Tattva. It is because of the dominance of the [power of] will that a balanced state of Jnana and Kriya exists in Sadashiva Tattva. When the power of knowledge (Jnana Shakti) becomes dominant, this is the Ishwara Tattva, and when the power of action (Kriya Shakti) becomes dominant, this principle is known as Vidya Tattva.
For the introduction in Kashmiri Shaivism, you may read the book The Secret Supreme by Swami Lakshmanjoo.