nepali weapons, usually khukuri, have this cut out, called either a 'cho' or 'kaudi (alt. kauri)'. there has been discussion as to what it represents and/or it's purpose. the answer is 'nobody knows'. some say it's religious, a hindu sacred cow toe mark, to they do come in other shapes (see attached), some saw it's to give blood a place to run off (if so it doesn't work). some say it's a sight for throwing it like a boomerang (when they're being humourous). most say a khukuri is not a real one without it. why one would be on a 'zulfigar' muslim sosun pata sword, i have even less of an idea. maybe a low caste hindu kami's (blacksmith's) protest
. many early khuks don't have them tho. a mystery wrapped up in a conundrum. puzzling ain't it?
i have seen a photo of another zulfiqar recurved wootz sosun pata sword with a tulwar hilt and knuckle guard - it also had a kaudi. also see below.