Delft(?) China (Chinese?) Bowl Blue and white, Tin glaze(?),Dutch? What ???

I believe this is a Delft Bowl circa 1640's or so , but I'm interested in any confirmation or information .My family going back to those days was in the business. I believe it's also called "tinware" and I think it's a "soft Paste" porcelain. It's quite large maybe 11 inches across (roughly and 6 or so inches tall.It has a crack all the way around but has not broken as of yet. Anyone with info on how to keep it from splitting, I would appreciate any help! (I just don't touch it!! )It was passed down through several generations in my family.(They were in the Dutch East Indies Trading Co.) Appreciate any help and comments! Thanks for looking!! (Flow Blue was the closest Secondary sub category)