I have acquired this large tea set and was wondering if anyone could tell me anything about it
The characters on the bottom of your pot simply say "Great Japan" and can be found on any number of manufacturer's ware. It's not a maker's mark. Judging by the style of the illustrations, I'd say it's not 'terribly' old meaning, they're more stylistic and modern than those of WWII vintage. Can you elaborate on what pieces this set consist of? Look for other marks on the bottoms different than this one?
It looks like lustreware or lustre ware.