After reading your post, is it reliable for beginners to buy guqin and second-hand piano? But I haven't touched the guqin at all. What is a qualified piano?

Don't buy it for beginners, Qin Gui. If you can't persist, your money will be wasted. If you really want to learn, you'd better buy a slightly better piano from the piano teacher in one step, instead of a factory piano of one or two thousand. One or two thousand pianos are cheap, but if you really want to improve, you won't be able to play for long. Of course, you can buy a second-hand piano, but it depends on what it is. A piano that can be used for a long time will never be much lower or even higher than the original price. As for this kind of piano with a hand of 2000 and a second hand of 800, it is really unnecessary to buy it if you throw it away after using it. Of course, now I'm worried about money. If I can't use it anymore, I know that buying a piano really needs one step.