उमामहेश्वरव्रतं—पञ्चाक्षरमन्त्रस्य माहात्म्यं, न्यासः, जपविधिः, सदाचारः, विनियोगः
छन्दो ऽनुष्टुप् ऋषिश्चात्री रुद्रो दैवतमुच्यते शिकारो धूम्रवर्णो ऽस्य स्थानं वै पश्चिमं मुखम्
chando 'nuṣṭup ṛṣiścātrī rudro daivatamucyate śikāro dhūmravarṇo 'sya sthānaṃ vai paścimaṃ mukham
Meternya ialah Anuṣṭubh; ṛṣi-nya ialah Ātrī; dewa penaungnya disebut Rudra. Suku benih (bīja) ialah “śi”, berwarna kelabu berasap; dan tempatnya ialah wajah Barat.
Suta Goswami (narrating mantra-viniyoga/nyasa details within the Purva-Bhaga discourse)
It gives the viniyoga markers—metre, seer, deity, bīja-syllable, and directional placement—used to correctly apply mantra-nyāsa in Linga/Rudra worship, aligning the sādhaka (pashu) with Pati through disciplined ritual order.
By naming Rudra as the devatā and assigning a directional “face,” it presents Śiva as the presiding consciousness of the mantra who manifests in ordered aspects (mukhas) while remaining the one Pati beyond all directions.
Mantra-viniyoga and nyāsa: fixing the mantra’s components (chandas–ṛṣi–devatā) and installing its power in a specific direction/face—supporting Pāśupata-oriented sādhana that loosens pāśa (bondage) through correct upāsanā.