Search:

it is not hamon, hamon is a result of differential treatment of a single piece of steel like this
http://red-dragonfly-sword.com/upload/userfiles/stachi_hamon01.jpg

Most Kamisori are forge welded...

that is where the foge weld between hard steel and the soft iron is, not a crack.

I do not think itis anything special , but you need to know how to properly wrap it on the handle.
You can also get an universal rubber handle by Tosuke.
I am sure on e-bay you can find one.

Technically yes but you can use it yourself , and with more practice you will get full quality shave from a kamisori.

I use both forward and back honing motion and it works fine. I do not kow if there is any real diffrence really.

I'll second Glen here,
I have not watched his vids but I found out that Coticule is great for starting work on Kamisori. You might be able to get a very nice edge of Coticule too, I personally...