Śiva-śakty-aikya-rūpiṇī शिव-शक्त्यैक्य-रूपिणी (999)

This is the most revered, admired, perplexed, incomprehensible and secretive form of the Divine Couple, the confluence of Śiva and Śaktī.  The universe is created, sustained, dissolved and re-created by them at their will that is indentured by the law of karma.
Saundarya Laharī (verse 1) says, “Śiva becomes capable of creating the universe, only when united with Śaktī, otherwise He is incapable of even a stir (known as spanda).” Śiva is also known as Parabrahman and Śaktī as ParāśaktīParabrahman is the static energy and is niṣkāma (devoid of  desire, disinterested and unselfish) in nature. The nature of Śiva is explained in Māṇḍūkya Upaniṣad (7), which says, “It is neither consciousness of what is happening within nor the consciousness of what is happening externally.  It is not conscious of all objects and it is not unconscious either. It is beyond perception of any organ, beyond thought and sound. In it there is only consciousness of the Self and there is a total cessation of the world as such. It is the embodiment of peace and all that is good. It is without a second.” This is the typical explanation of the Brahman that is preternatural and interpenetrating.
Śaktī is primordial and latent energy of Śiva that alone manifests as the universe, its sustentation and disintegration and recreation. The consciousness referred by Māṇḍūkya Upaniṣad is nothing but the domain of Śaktī. That is why it is said that Śaktī is the primordial and latent energy of Śiva. She exists along with Śiva and cannot be separated. If Brahman and consciousness are discriminately differentiated out of nescience, the question of creation and existence does not arise. In reality, such differential existence does not prevail. But for easier understanding of the complex issue of creation, Śiva and Śaktī have been perceived as two different aspects of the same entity. One cannot segregate the heat produced by the fire from the fire itself. The heat of the fire is primordially present in the fire. Neither fire, not heat can be of any use unless they subsist together. This is a typical example showcasing Śiva and Śaktī, the one without the other remain only an inert.
Śiva is Self-illuminating.  Without His existence, the universe will be plunged into darkness. Śiva is present in prakāśa (illuminating) form.  Prakāśa can be explained as visible, shining, universally noted, brightness, lustre, splendour, etc.  Prakāśa also refers to Śiva and the Brahman.  Śaktī is His vimarśa form.  Vimarśa can be explained as reasoning, knowledge, consideration, reflecting etc.  In spite of Śiva being the grandeur amongst the cognized existences, He cannot realise His own incomparable splendour without something that is able to reflect His grandeur.  This is like a human not able to see his own self without an object that is capable of reflecting his image.  Śaktī acts like a reflecting mirror where Śiva is able to realise His Reality, like a mirror reflecting the image of a person who stands before it.  Pure consciousness is Śiva and realising the pure consciousness is Śaktī.  If Śiva is not present, the consciousness itself does not exist.  If Śaktī is not present, the presence of consciousness cannot be realised.  In the state of prakāśa ‘I’ and ‘This’ stand united and in the vimarśa aspect ‘This’ is separated from ‘I’.  Therefore prakāśa aspect is ‘I + This’ and vimarśa aspect is ‘This’ alone.  ‘I’ is the origin of the universe and ‘This’ is the expansion of the universe. Śiva is cit and Śaktī is citiCit means foundational consciousness and citi means the consciousness that brings about cognitive operations. Śaktī segregates I and This.  Without Śaktī this vital segregation cannot take place. Śiva causes the initial pulsation for creation that is carried forward by Śaktī.
Śaktī pushes forward the throb created by Śiva through different principles or tattva-s (thirty six) and sustains it through Her māyā or illusion. Māyā is the sole factor that separates a soul from the Brahman. She is the manifested conglutination of Śiva and Śaktī and therefore She is both the seed and the sprout.  This also drives home the point that for creation, two objects are required. For example, a soul alone cannot be born on its own. It has to come into contact with prakṛti or Nature in order to manifest. Procreation is not possible without conjoining of masculine and feminine energies.
Moving on from the perceptible to subtle, a lot more is said about Their subtle conjugation. They are referred as two bindu-s (dots), white and red, denoting Śiva and Śaktī respectively. These two bindu-s, in mutual conjunction expand and contract. When they expand, the creation takes place by means of vāc (word) and artha (lit. meaning). Vāc means the Śabda Brahman and artha means thirty six  tattva-s or principles. These two bindu-s which enter one another are known as Kāma-Kāmeśvarī. Śiva, the Supreme is in the form of the first alphabet of Sanskrit A (अ), is the cause of all sounds of Veda-s. He attains the form of a bindu after having entered His own vimarśa form, Śaktī, in whom the entire universe is dissolved. Like prakāśa form of bindu entering the vimarśa form of bindu, vimarśa form of bindu also enters prakāśa form of bindu, which is already within it. As a result of this conjugation, a third bindu called as miśra bindu is born.  Miśra means combined.  Now there are three bindu-s, white, red and miśra. These three bindu-s form a triangle, red and miśra are below and the white bindu is placed above them causing a perfect triangle. The miśra bindu has all the tattva-s or principles within itself and is the cause for further creation. This is the innermost triangle of Śrī Cakra. When these three dots are connected, the three connecting lines represent all the triads such as three guṇa-s, three stages of consciousness, icchā, jñāna and kriyā śaktīs, etc. This triangle becomes the cause for creation beginning with Brahma, Viṣṇu, and Rudra.  These three dots are also referred as sun (top), moon (right) and fire (left). There is an inverted triangle below the three dots. The three connecting lines of this lower triangle represent three kūṭa-s of Pañcadaśī mantra (nāmā 89). The upper most bindu (of the upper triangle) is the face of Śaktī (the third eye, denoting dissolution, the two lower dots represent Her bosoms (representing nourishment or sustenance) and the inverted triangle below mean Her procreative organ (representing creation). This is known as kāmakalā and is considered as the most secretive principle of Śiva-Śaktī union.
The explanation provided in Varivasyā Rahasya, the treatise on Pañcadaśī mantra, corroborates with the explanation offered for Kāma Kalā Vilasa, yet another treatise on Śrī vidyā. Varivasyā Rahasya (verses 69 to 72) says, “Śiva and Śaktī embrace each other. The Brahman (Śiva) with the desire to create glanced on His other half, His consort and assumed the form of a bindu (referring to male procreative fluids), into which Śaktī enters assuming the form of another bindu (representing female procreative fluids).  The mixture formed by their aggregation is known as aham or I, the ego.”  This is the subtle form of the union of Śiva and Śaktī.
One more interpretation is possible for this most secretive nāma of this Sahasranāma. The scene goes like this. Śiva is sitting alone meditating, His usual posture. Śaktī enters the place of Śiva. Śiva wakes up. First, Śaktī sits next to Śiva. Later on She moves to His left lap and finally occupies His entire left side, blessing the universe with their Ardhanārīśvarā form causing creation and sustenance. When Śaktī moves away from Śiva, He starts His cosmic dance, causing annihilation. Śaktī witnesses His cosmic dance (nāma 232 and 571).
Saundarya Laharī (verse 34) says, “I consider your pure frame to be Śiva.  Hence the relationship of the principal and the accessory exists in common among you both who as transcendent bliss and consciousness are equipoised.”
This nāma salutes Her undifferentiated form from Śiva, that is inseparable eternally. Their union is also known as Śiva-Śaktī sāmarasya, the identity of Consciousness, where identical state prevails in which all differentiation has disappeared.