Although I noticed African knives have been discussed occassionally here since appox 2007 , I could not find anything on Scarification (AKA tattoo) knives?
Whilst it was / is such an important part of their cultural heritage. Next pricewise, these knives are not cheap at all, compared to the "normal" ones...
Quite frequently present in pre 50-ies / 60-ies Africa, one does not see it anymore that often. Also North Africa, especially the Magreb.
I personally recall the first generation Amazigh women in the early 70-ies in the Netherlands and Belgium wearing proud their green coloured tattoos on their chin and forehead. But that's another story...
Back to the Congo. Enclosed a couple of pics of the scarification results and some of the knives, which are between 10 and 19 cm long.
A link on how this is done ( from Benin ) is not for the faint-hearted though...
https://www.youtube.com/watch?v=Lfhot7tQcWs