6.1.134
सोऽचि लोपे चेत् पादपूरणम्
Operational rule vidhi
The सुँ-प्रत्यय of सः gets removed when followed by an अच्, provided that (only) by doing so, the पाद can be completed.
Word by word (padaccheda)
Substitute / term सः prathamā · ekavacanaRight context saptamī · ekavacanaRight context saptamī · ekavacanaIndeclinable चेत् avyayaSubstitute / term पादपूरणम् prathamā · ekavacana
- Substitute / term Prathamā (1st case): in operational rules, the substitute or the thing introduced; in definitions, the term or its referent.
- Right context Saptamī (7th case): "when X follows", the operation applies to what precedes (1.1.66 तस्मिन्निति निर्दिष्टे पूर्वस्य). Also a condition or domain ("in the sense of").
- Indeclinable An avyaya such as च "and", वा "optionally", न "not".
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
सः चेत् पादपूरणम्
Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.
Commentary
The case affix of सस् 'he', is elided before a vowel, if by such elision the meter of the foot becomes complete.
Karika
सैष दाशरथी रामः, सैष राजा युधिष्ठिरः॥
सैष कर्णो महात्यागी सैष भीमो महाबलः ॥
Thus सेदु राजा क्षयति चर्षणीनाम् (Rig I.32.15) सौषधीरनुरुध्यसे (Rig VIII.43.9). The case-ending being elided, the Sandhi takes place. Why do we say 'when by such elision the metre of the line is completed'? Observe स इव व्याघ्रो भवेत् ॥ The word अचि in the sutra is for the sake of distinctness:for the purposes of metre would not have been served by eliding the affix before a consonant, for then the syllables would remain the same. It is by sandhi that a syllable is lessened; and sandhi would take place only with a vowel. Some explain the word पाद as 'a foot of a Sloka' also, and according to them this rule is not confined to Vedic metres only. Thus we have:- सैष दाशरथी रामः, सैष राजा युधिष्ठिरः, सैष कर्णो महात्यागी सैष भीमो महाबलः ॥
Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.