हशि च

Operational rule vidhi

A रुँ letter that follows an अप्लुत-ह्रस्व-अकार and is followed by a हश् letter is converted to an उकार.

Word by word (padaccheda)

Right context saptamī · ekavacanaIndeclinable च avyaya

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

च

Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.

Commentary

The उ is the substitute of रु (the र् substitute of a final स् 8.2.66) when it is followed by a soft consonant and preceded by an अप्लुत short अ।
The हश् pratyahara includes all sonants or soft consonants. Thus पुरुषो याति or हसति or ददाति &c.

Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.