Perfect, TYSM!It's stunningIt's most likely a 1-series lambskin from the mid 1980s. It's rare; I've seen just a few through the years (in black, on ebay) and never on traditional reseller sites. It's considered a wave pattern or circular wave stitch. It wouldn't have a collection name so you would describe it as a 'vintage flap with wave pattern.' It would have the gold-plated hardware, too. I'll link something similar: https://www.tradesy.com/i/chanel-cl...on-5676-black-lambskin-shoulder-bag/25842459/
HTH