I'm not sure if it's "OK" to resurrect this thread, about 8 months since it's start... but I thought this would interest some people. I did not have a good clear photo of a Kerala-katar used in Kalaripayattu, and I don't think many outside of Kerala and Kalaripayattu training know much about it specifically...
link the Kerala-katar
Photo edited to be "right-side up"
Found this guy while looking up Taiwanese aboriginal knives and Native American quivers in the database.
Good enough example? Any interest for discussion?
Could this Kerala / Kalaripayattu style katar simply be a martial arts specialization weapon? Some martial arts have a specialized weapon that their art is often known by... or a master fighter had taken a common or uncommon weapon and further modified it and developed further techniques for it that is carried down in his fighting art.