This sword has been very divisive among those who see it; I've had an even number of people dismiss it as a forgery as confirm it as authentic. Now, without a doubt the wood fittings are modern, but the blade itself shows a visible grain, a strong convex shape and as you run a (gloved) hand along the blade, you can feel small irregularities and waves which could only come from forging.
I would say the tsuba etc. all pre-date the sword; from the condition of the tang I would probably guess the sword is WWII-vintage, though the tang may have been cleaned and/or tampered with in a Chinese chop shop (it shows file marks along the edges, but at the same time there are a few blackened divets that to me look like the marks of a cross-peen hammer made during forging. Side note, I've been a practicing blacksmith and welder for several years now.)
The blade has become cloudy, but I would hesitate to say it needs a new "polish" unless by polish you mean an electric buffer and some jeweler’s rouge. As per the history of the sword in my possession, I bought it as a toy on the internet for one cent ($80 shipping from China I didn't see until it was too late). Any opinions on the quality/history of the sword? Would it take a full polishing to retrieve the luster of a proper blade? Is it only a paperweight? Thank you all for any opinions you may have, I'll post more pictures of the tsuba in the appropriate forum.