Pāṇini sūtras

Before the affixes iṣṭha, iman and īyas, the ṛ of ṛju may optionally be changed to ra in the Chhandas.

German Im Veda kann diese Substitution auch bei ṛju eintreten. (162)

1. vibhāṣā+ṛjoḥविभाषा+ऋजोः

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   vव्	vibhāṣविभाष्	vibhāṣāविभाषा	option	vibhāṣविभाष् + plus āआ
   ṛऋ	ṛjuऋजु	ṛjoḥऋजोः	ṛju [word]ऋजु [wओर्द्]	ṛjऋज् + plus oḥओः

2. chandasiछन्दसि

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   cच्	chandasछन्दस्	chandasiछन्दसि	Veda	chandछन्द् + plus asiअसि

Anuvṛtti

1. bhātभात् 6·4·22

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   bब्	bhaभ	bhātभात्	bhaभ	bhभ् + plus ātआत्

2. bhasyaभस्य 6·4·129

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   bब्	bhaभ	bhasyaभस्य	bhaभ	bhभ् + plus asyaअस्य

3. iṣṭha+ima+īyassuइष्ठ+इम+ईयस्सु 6·4·154

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   iइ	iṣṭhanइष्ठन्	iṣṭhaइष्ठ	iṣṭhanइष्ठन्	iṣṭhइष्ठ् + plus aअ
   iइ	imanइमन्	imaइम	imanic	imइम् + plus aअ
   īई	īyasईयस्	īyassuईयस्सु	īyasunईयसुन्	īyasईयस् + plus suसु

4. ṛ+taḥऋ+तः 6·4·161

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   ṛऋ	ṛऋ	ṛऋ	ṛkāraऋकार	ṛऋ
   tत्	tत्	taḥतः	TT	tत् + plus aḥअः