6.2.162
बहुव्रीहाविदमेतत्तद्भ्यः प्रथमपूरणयोः क्रियागणने
Operational rule vidhi
In a बहुव्रीहि समास , after the words इदम् , एतद् and तद् the last syllable of प्रथम and of a proper ordinal numeral as the acute accent (उदात्त) when the number of times of an action is meant.
Word by word (padaccheda)
Right context बहुव्रीहौ saptamī · ekavacanaLeft context इदम्- एतत्- तद्भ्यः pañcamī · bahuvacanaTarget प्रथमपूरणयोः ṣaṣṭhī · dvivacanaRight context क्रियागणने saptamī · ekavacana
- 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").
- 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).
Full reading
बहुव्रीहौ इदम्-
Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.
Commentary
In a बहुव्रीहि समास , after the words इदम् , एतद् and तद् the last syllable of प्रथम and of a proper ordinal numeral as the acute accent (उदात्त) when the number of times of an action is meant.
Thus इदं प्रथमं गमनं भोजनं वा = स इदमप्रथमः꣡ 'this is the first time of going or eating'. इदं द्वितीयः꣡, इदं तृतीयः꣡, एतत्प्रथमः꣡, एतद्द्वितीयः꣡, एतत्तृतीयः꣡ तत्प्रथमः꣡, तद्द्वितीयः꣡ तत् तृतीयः꣡ ॥ Why do we say 'in a Bahuvrihi?' Observe अनेन प्रथमः = इदंप्रथमः ॥ Here the first member being in the third case retains its accent by 6.2.2. Why do we say "after idam &c". Observe यत्प्रथमः = यःप्रथमं एषाम्, here the first term retains its accent by 6.2.1. Why do we say 'of prathama and the Ordinals'? Observe तानि बहून्यस्य = तद्बहुः ॥ Why do we say 'in counting an action'? Observe अयं प्रथम एषां = त इद प्रथमाः ॥ Here substances are counted and not action. Why do we say 'in counting'? Observe अयं प्रथम एषां = इदं प्रथमाः i.e. इदं प्रधानाः ॥ and the word प्रथम means here 'foremost', and is not a numeral. When the कप् affix is added, the acute falls on the last syllable preceding कप् ॥ As इदं प्रथमकाः ॥ The Bahuvrihi governs the subsequent sutras upto 6.2.178.
Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.