mikerault
Contributor
A good one can cost up to several thousand dollars. In the handle will be either a single pin or maybe 2 pins if it is a full tang. Use a small drift to carefully remove these and the handle will slip off (I found a length of pvc just big enough around to fit the blade and longer than the blade portion helps, you just use the knock technique to loosen the handle). Underneath will be a full tang if it is a good one with Japanese characters giving the makers name, date, etc. If the tang has nothing on it then it is a knockoff. Are they stainless? If so, they are a knockoff. Real Katanas will be high carbon steel, either "folded" or not (depending on age, quality of initial steel, technique used) There should be a wavering temper line on the sharp edge, if that appears to have been ground in or etched in, then it is not a real blade but a knock off. Also, if there are characters stamped into the blade itself, then it is probably a knockoff. Some blades may have a pattern in the blade itself, these are usually ones that have been folded.
