एकस्य सकृच्च

Operational rule vidhi

The word सकृत् is substituted for एक before the affix सुच् (स्) when an action is to be counted.

Word by word (padaccheda)

Target एकस्य ṣaṣṭhī · ekavacanaSubstitute / term सकृत् prathamā · ekavacanaIndeclinable च avyaya

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.
Indeclinable An avyaya such as च "and", वा "optionally", न "not".

Dotted words are technical terms. Hover or tap one to see its card.

Full reading

एकस्य सकृत् च

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

As a rewrite rule (sketch from case endings)

एकस्य → सकृत्

Replace ekasya with sakṛt. Inherited words (anuvṛtti) may add further conditions.

Commentary

The word सकृत् is substituted for एक before the affix सुच् (स्) when an action is to be counted.
This debars कृत्वसुच् ॥ The 'repetition' being impossible, the action alone is counted : so the anuvritti of क्रिया only runs into this sutra and not of अभ्यावृत्तिः ॥ Thus सकृद्भुङ्क्ते "he eats once" सकृदधीते ॥ The स् of सुच् is elided by 8.2.23. But not here in एकः पाकः as being against usage.

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