I am not a collector of Japanese swords, originals are too expensive. I have handled a number, and there are several orders of magnitude Chinese replicas on the market than original Japanese swords. I will say, not every Japanese sword is master class workmanship, I handled one, that the Iwo Jima Veteran personally took off the body of the Japanese Officer whom "we got him too!". I knew this gentleman for a couple of decades, so I know he was not blowing smoke up my orifices. Sammy brought it, and other items, back in his duffle bag. His sword had better workmanship than the fake Chinese replicas I have handled, but, it was not perfect.
The thing is, you have to have the sword in your hand to really evaluate its quality. The first thing I do is hold the sword out at arms length and examine whether or not the edge is straight. Chinese replicas that I own, the edge more or less wanders, and the bevel is not even. Sammy's Japanese sword, the edge was straight, but I was not impressed with the evenness of the bevels. Not horrible, but not perfect. His sword scabbard was very deteriorated, and had writing. Sammy said, someone who read Japanese told him it was Patriotic slogans. I have been told most of the WW2 era Officer swords were quickly made, functional pieces, but made to a price point.
The antique replica Chinese swords quickly reveal themselves by the quick and shoddy workmanship they show, they are not at all weapons of war, and don't feel like one. I do think the better Cheness swords, of which I have a couple, show good workmanship for their price point, and feel right for people chopping. Too bad Cheness has stopped importing his swords.
