Alex,
Opening an old/very old thread once more:-).
Hindu Arms and Ritual by Robert Elgood, page 107 the column to the right.
"The Marathas marked the trident on their swords and canon in honour of Durga...."
I cant say it is a Maratha blade, but in these parts some blades were marked with a katar, as far as I know.

Jens,

Thank you for reopening this vintage thread from the Archives. Jim's comment about a particular group in Gujarat that swore oaths on the katar has prompted me to write to my princely contact in Gujarat to see if we can better define which of the various Rajput clans may have used that practice. This is the same gentleman about whom I wrote to you previously. He's a busy man so it may take a little while to retrieve his answer.

All the best,

Ian.

Ian,
Very long time ago I read about a habit they had - in Gujarat I think. When someone had made a promise, and did not keep it, he should do something dramatical to his arm with his katar - I am sorry but I have forgotten what it was. In stead of doing this they made a cut on the arm, and the text said,that some had quite a lot of cuts on the arm.