For me this season is the season of deep immersion into Siddhanta of "Shree Vishnu-Purana", but occasionally I turn to Sanskrit-Hindi scans of other Puranas as well.
One of the Chapters in "Shree NaraSimha-Purana" is dedicated to Shree Ashtakshara-Mantra of Bhagavan Shree Narayana.
Below is a little synopsis of Narayana-Mantra-Siddhanta from "Shree NaraSimha-Purana".
Shree Ashtakshara Mantra is suitable even for those, who don't have an adhikara for complex Vaidik/PanchaRatrik rites.
The unique feature of Shree Narayana-Ashtakshara Mantra is that it causes "immediate enjoynment" ("tatkala prasanna") of Bhagavan Shree Vishnu and grants Sayujya-Mukti without any hindrances!
If you make Pujas with Shree Narayana-Ashtakshara-Mantra, then there is no need to visit Vaishnava-Tirthas or make complex Vaishnava-Yajnas, because Shree Narayana-Ashtakshara-Mantra grants
phalas (results) of all Vaishnava Yajnas/Tirthas visiting immediately!
phalas (results) of all Vaishnava Yajnas/Tirthas visiting immediately!
"Shree Narasimha-Purana" also mentions Indra as a sadhaka following to 8-Syllable Mantra of Bhagavan Shree Narayana upasana (please see Sanskrit-Hindi below)!
Shree Narayana-Mantras, without any doubt, belong to Vaishnava-Raja-Vidyas: in "Shree NaraSimha-Purana" Markandeya Rishi mentions not only Indra (the Raja of Svarga-Loka), but tells about this Vidya to Sahasranika Raja as well.
Indra has a special connection with Shree Ramanuja-Sampradaya, because Shreemati MahaLakshmi-Devi granted "Shree Lakshmi-Tantra"-Vidya to Indra at first, so you can often meet Indra both in Shakti-Vidyas and Vaishnava-Vidyas!
The above-mentioned Siddhanta (and more!) in Sanskrit-Hindi:
Vishnudut1926, Moscow, November 2017