(archaic) Like the chandrakala and circular virama, the vertical bar virama was used to delete the inheret vowel from the consonant but it was used between 1700s to 1860s (possible even before) in loanwords while circular virama in native words at the same time and chandrakala in later times.[1]
The bar virama was placed directly above the letter while chandrakala and circular virama at the top right. In older attestations it was allowed to cut through the consonant.
Bar virama + letter later evolved into the chillu letters.
While writing it may sometimes be confused with the dot reph ൎ but both of them are used for different purposes.
