6.3.135
द्व्यचोऽतस्तिङः
Operational rule vidhi
A tense affix ending in अ is lengthened in the ऋग्वेद when the verb consists of two syllables.
Word by word (padaccheda)
Target द्व्यचः ṣaṣṭhī · ekavacanaTarget अतः ṣaṣṭhī · ekavacanaTarget ṣaṣṭhī · ekavacana
- Target Ṣaṣṭhī (6th case): names what gets replaced, "in place of X" (1.1.49 षष्ठी स्थानेयोगा).
Dotted words are technical terms, dashed ones pratyāhāras (names for classes of sounds or affixes). Hover or tap one to see its card.
Full reading
द्व्यचः अतः
Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.
Commentary
A tense affix ending in अ is lengthened in the ऋग्वेद when the verb consists of two syllables.
Thus विद्मा हि त्वा सत्पतिं शूर गोनाम् &c. See Rig III.42.6, विद्मा हि तस्य पितरम् &c. But not here देवा भवत वाजिनः, as the verb consists of more than two syllables: not also here आ देवान् वक्षि यक्षि च as the verbs do not end in अ ॥
Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.