deriv SD cv (586) ashtadhyayi.com hei.de L 586 ETT STT a 8.2.40 ALPH OLDHOMEPAGE NEWHOMEPAGE

jhaSas ta;thor dho 'dhaH

झषस्तॱथोर्धो ऽधः ONPANINI 82040

Replace t त् th थ् with dh ध् after /jhaS, unless after dadh- दध्.

budh- बुध् + /kta
→ budh- बुध् + dha ध by this rule
→ bud- बुद् + dha ध by jhalAJjazjhaz...
→ !**buddha- बुद्धॱ "awake"

labh लभ् + /kta
→ labh लभ् + dha ध by this rule
→ !**labdha- लब्धॱ "gotten" by jhalAJjazjhaz...

nah नह् + /kta
→ **naddha- नद्धॱ "tied"

Why do we say a-dhas अॱधस् "except after dadh दध्"? What is that dadh दध्?

That dadh दध् is the base dhA धा + /zlu → **dadhA- दधाॱ from the root dhA धा "put, hold", but only when it has lost its A आ by znAbhyastayor....

Because of this exception, **dadhA- दधाॱ + /tas does not make dhaddhas. Instead, we just get dhad धद् + /tas —

dhA धा + /laT /tas
→ **dadhA- दधाॱ + /tas
→ dadh- दध् + /tas by znAbhyastayor...
→ dhadh- धध् + /tas by << dadhastathozca
→ dhat धत् + /tas by kharica
→ **dhattas धत्तस् "they2 hold"

Now, the wording of the sUtra is sort of funny. How did you figure out that "jhaSas + adhas" means "after a /jhaS that is not the dh ध् of dadh दध्" and not just "after a /jhaS that is not dh ध्", which seems to be the simplest interpretation?

To figure that out you need some extreme Sherlockholmian thinking. As you appear to like that sort of puzzlesolving, I won't tell you any spoilers.