Tithi-Nirṇaya for Vratas: Ekādaśī Rules, Saṅkrānti Punya-kāla, Eclipse Observances, and Prāyaścitta
संपूर्णैकादशी शुद्धा द्वादश्यां च प्रतीयते । त्रयोदशी च रात्र्यंते तत्र वक्ष्यामि निर्णयम् ॥ ४२ ॥
saṃpūrṇaikādaśī śuddhā dvādaśyāṃ ca pratīyate | trayodaśī ca rātryaṃte tatra vakṣyāmi nirṇayam || 42 ||
Khi ngày Ekādaśī trọn vẹn và thanh tịnh, phải hiểu là nó liên hệ (rơi vào) Dvādaśī; và nếu còn kéo dài đến cuối đêm Trayodaśī, thì về trường hợp ấy ta sẽ nói rõ sự quyết định đúng đắn cho việc hành trì.
Sanatkumara (in dialogue with Narada)
Vrata: Ekadashi
Primary Rasa: shanta
Secondary Rasa: bhakti
It frames Ekādaśī as a dharmic vrata requiring correct timing (nirṇaya); purity of the tithi safeguards the spiritual merit of the vow and its Vishnu-oriented devotional purpose.
By emphasizing precise observance of Ekādaśī, it supports disciplined bhakti—devotion expressed through regulated fasting and adherence to sacred time, rather than mere sentiment.
Vedāṅga Jyotiṣa/Kalpa-style tithi-nirṇaya: recognizing when Ekādaśī is “śuddhā” and how to decide observance when it overlaps into Dvādaśī or even extends toward Trayodaśī night-end.