आदिः सिचोऽन्यतरस्याम्

The सिच् Aorist, the first syllable may optionally have the acute accent.
The word उदात्त is understood here. Thus मा हि का꣡र्ष्टाम्, मा हि कार्ष्टा꣡म्; मा हि ला꣡विष्टाम् or मा हि लाविष्टा꣡म् ॥ In the last example the accent is on पि; and the reason why मा and हि are used in these illustrations, has already been explained in 6.1.161. The indicatory च् of सिच् the shows that by 6.1.163 the acute will be on the otherwise unaccented augment इट्, when it takes this augment. The सिच् being a वलादि affix will take the augment इट् 7.2.35, and it is a general rule that augments are unaccented; so in the above the वि would have been unaccented, and the accent would have been on the final, but for the indicatory च् of सिच्, which otherwise would find no scope. Thus वि gets acute.

Vart:- An affix having an indicatory प् (पित्) when coming after an Aorist by सिच् without the augment इट् (अनिट् सिच्) is in one alternative udatta (in the other, it is non-acute). This vartika restricts the scope of the sutra with regard to पित् affixes. Thus we get the following two forms, which otherwise would have one form only by dhatu-accent, namely, acute on the first, for पित् is anudatta. Thus माहि का꣡र्षम् or मा हि कार्ष꣡म् ॥ But when it takes the इट् augment, there are two forms (Ist.) मा हि ला꣡विषम् as a तिङन्त, (2nd.) मा हि लाविष꣡म् accent on वि 6.1.163. but never मा हि लाविष꣡म् ॥ When however the augment अ is added, the accent falls on this augment 6.4.71.