'ra' Rule

The rules pertaining to writing 'ra' -

• If a र् comes before another consonant, then it is represented as 'a half sickle on top of the following consonant'.  Ex. र्क, as in तर्क (logic)

• If a full र comes after any other half consonant, it takes the form of 'a slash under the consonant preceding it'.  Ex. क्र तक्र (curd).