Glad you're with us too. I'm sure some of our nihonto people will give you better advice than I.
A few things I have learned:
- Study, study, study - knowledge is power and research can help you find what you like, and then you will also be less likely to get screwed.
- Go to reputable dealers with good reputations. You can take a piece back if you discover that something is wrong with it.
- Talk to knowledgeble people or even join a nihonto society. They know the ins and outs, and who the good players are.
I hope this helps. It sure has helped me avoid some very ugly losses. I am still not ready for getting into nihonto - yet (still studying)
Now if you aren't ready for nihonto but are looking for gunto and kai-gunto stuff, I still say the same thing. There are fakes on the market in both nihonto and gunto/kai-gunto stuff out of China.