both chordophone (弦鸣乐器)and percussion instruments. --所以钢琴才那么复杂啊。
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The piano is one of the most-popular musical instruments in the world. But peek inside it, and you’ll quickly discover that it is also among the more-complex instruments. You might also begin to wonder what type of instrument it is—percussion or stringed?
Inside a piano, there are strings, and there is a long row of uniformly rounded felt-covered hammers. In the traditional Hornbostel-Sachs system of categorizing musical instruments, the piano is considered a type of chordophone. Similar to a lyre or a harp, it has strings stretched between two points. When the strings vibrate, they produce sound. On a piano, however, those vibrations are initiated by hammers hitting the strings rather than by plucking or by moving a bow across them. So, the piano also falls into the realm of percussion instruments. As a result, today the piano is generally considered to be both a stringed and a percussion instrument.