Sorry to be late to the party here - I was waiting to see if
@Mark had some wisdom to share. Based on my limited knowledge, here are a few pointers :
1. As far as vintage Kamis go, there are two brands that stand at the top of the podium - Iwasaki and Henkotsu. Iwasaki still make razors, but expect to pay around U$350 for a new one, and sky's the limit for a top quality NOS oldie (I've seen U$10k+) There are lots of Henkotsus on Ebay, and you should be able to get a very good one for a fair price.
2. Having said that, there aren't many crappy Kamisoris. For real quality, look for good steel - Swedish steel or (more expensive) Tamahagane (samurai sword or jewel steel)
3. If buying secondhand, look carefully at the photos of the Omote side of the Kami for hone wear. The omote is the bevelled side, not the full hollow ground side with the maker's stamps. You'll see where the Kami has been honed as two shiny lines, one at the cutting edge and the other at the top of the bevel. You don't want to see big wide lines - they're a sign that the Kami has been honed a lot and lost a fair bit of metal in the process. Ideally, these lines won't be much more than 1mm wide.
4. The photo you posted above is likely a Henkotsu Kamisori, and the construction method dates back a long long way. The rectangular piece that includes the cutting edge used to be made from Tamahagane steel - expensive and in short supply. So the blacksmiths used as little of it as necessary, and forged it onto a soft iron handle and frame. The same technique is still used by some makers, even though few of them use Tamahagane steel these days. This construction is a sign of skilled blacksmithing, and some of the vintage Iwasaki Kamisoris show extraordinary virtuosity at it - an evenly wavy line where the two pieces of metal join together, along with a different degree of surface polish for each part.
5. As with most things in life, you get what you pay for. While it's possible to find a good instrument secondhand for a bargain price, don't expect it. My personal suggestion would be to budget in the $100-200 range for a first shot. If you buy a real cheapie, you run a reasonably high risk of having a poor first experience for your first Kamisori encounter. Obviously this isn't likely to encourage you to keep going with it
6. No matter what you end up getting, I strongly recommend you send it to
@Mark to be properly bevel set and sharpened before using it to fillet your face. It takes experience to set one up from scratch, so leave that to a pro. That way you can maintain your own shaver with confidence.
If you find something you think you might go for, I'm happy to have a look at it if you PM me the details.
Calling
@Mark - can you add anything to this or correct anything I've said that may need correcting?
