उमामहेश्वरव्रतं—पञ्चाक्षरमन्त्रस्य माहात्म्यं, न्यासः, जपविधिः, सदाचारः, विनियोगः
अङ्गन्यासं ततः पश्चाद् अक्षराणां विधिक्रमात् मूर्धादिपादपर्यन्तम् उत्पत्तिन्यास उच्यते
aṅganyāsaṃ tataḥ paścād akṣarāṇāṃ vidhikramāt mūrdhādipādaparyantam utpattinyāsa ucyate
其后当行支分安置(aṅga-nyāsa)。再依真言音节之仪轨次第,自顶轮至足下次第安置,此名为显现安置(utpatti-nyāsa),即“显生之nyāsa”。
Suta Goswami (narrating Shiva-puja vidhi to the sages of Naimisharanya)
It teaches the preparatory inner-ritual for Linga-puja: installing the mantra’s syllabic power on the sādhaka’s body so the worshipper becomes fit to approach Pati (Shiva) with a consecrated mantra-body.
By prescribing utpatti-nyāsa, it implies Shiva as Pati whose śakti manifests as mantra and pervades the whole body from head to feet—revealing Shiva-tattva as all-pervading consciousness that can be invoked and stabilized through disciplined ritual awareness.
Aṅga-nyāsa followed by utpatti-nyāsa—sequential placement of mantra syllables across the body (from crown to feet), a Shaiva mantra-yoga method used in Shiva-puja and Pashupata-oriented sādhanā.