[Jim McDougall]

While extremely limited in my understanding of most martial arts, the katar is a most interesting weapon, which we have discussed considerably over the years. It seems that the armour piercing (malle perce) feature of strengthed tip is considered more prevalent in areas to the north where chain mail was more typically present. In the central and southern regions, such armour, while certainly nominally present, was not as common, so armour piercing weapons were not typical either.

The katar itself, much as the pata, its sword length counterpart, the gauntlet sword, was initially and more commonly a slashing weapon. The Mahrattas, one of the earlier groups generally held to have been among the earliest users of these weapons, are known for thier slashing preference with edged weapons, and typically were against the use of the thrust.

It is my understanding that among the earliest katars, especially those in Mahratta regions to the west, cut down European blades were used in them. While straight blades of course, they certainly would not have been for armour piercing any more than the original sword blade was, and the slashing cuts probably parallel to any other straight blades use.

I havent looked further into notes on these curved blade examples yet, but I would be inclined to think of them as to the northwest, and perhaps favored as a hunting type weapon. It is known that in these regions, among Mughals and Rajputs, to hunt tigers etc. with the katar was a pronounced mark of bravery, and the curved, uptick blade is in my understanding for a thrust and upward tear.
OTH, the curved blade as seen it seems in the slashing sense does, in the same effect as a sabre in providing more cutting surface in the movement of the cut.
Just cursory thoughts, and I hope they might be of some use.

All the best,
Jim