6.1.103
तस्माच्छसो नः पुंसि
Operational rule vidhi
When the rule 'प्रथमयोः पूर्वसवर्णः' is used to create a पूर्वसवर्णदीर्घ for a पुंलिङ्ग word in presence of the शस्-प्रत्यय, then the सकार of the शस्-प्रत्यय is converted to नकार.
Word by word (padaccheda)
Left context तस्मात् pañcamī · ekavacanaTarget शसः ṣaṣṭhī · ekavacanaSubstitute / term नः prathamā · ekavacanaRight context पुंसि saptamī · ekavacana
- Left context Pañcamī (5th case): "after X", the operation applies to what follows (1.1.67 तस्मादित्युत्तरस्य). Also used for limits and sources.
- Target Ṣaṣṭhī (6th case): names what gets replaced, "in place of X" (1.1.49 षष्ठी स्थानेयोगा).
- 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").
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
तस्मात् शसः नः पुंसि
Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.
शसः → नः / तस्मात् पुंसि
Replace śasaḥ with naḥ when it comes after tasmāt when puṃsi follows. Inherited words (anuvṛtti) may add further conditions.
Commentary
After such a long vowel homogenous with the first, न् is substituted for the स् of the Acccusative case affix शस् in the masculine.
Thus वृक्ष + शस् = वृक्ष + अम् = वृक्षान् ॥ So also अग्नीम्, वायून्, कर्तॄन्, होतॄन्, पण्डकान्, स्थूरान्, अरकान्, पश्य &c. All these are masculine nouns. Now the word चञ्चा formed by the elision of कन् meaning a figure like a चञ्चा 5.3.98, may refer to both the males and females. It will however retain its feminine form though referring to a male being (See लुपि युक्तवद् व्यक्ति वचने (1.2.51). In forming the accusative plural of चंचा, the स् will not be changed into न् ॥ Thus चंचाः पश्य, वध्रिकाः पश्य ॥ Why do we say 'after such a long vowel homogenous with the first'? The rule will not apply if the long vowel has resulted by being a single substitute for the antecedent and the subsequent. Thus आ is substituted for ओ + अ by 6.1.93. Here स् will not be replaced by न् as गाः पश्य ॥ Why do we say 'of the Accusative plural'? Observe वृक्षाः, प्लक्षाः endings in जस् Nominative Plural. Why do we say "in the masculine?" Observe, धेनुः, बह्वीः, कुमारीः ॥
Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.