I was looking at a Masahiro Virgin Caron santuko, but the belly of the blade is not quite flat enough for that I need. So, that opens me up to consider other carbon knives. The merchant (Knife Merchant o fSan Diego) said the knife develops a nice patina after a few uses, this avoiding staining of things like onions. That matters to me since that is one of my main uses. Is that unique to the Masahiro or can I expect other carbon knives to do the same?