Were there any paper money in ancient China? If so, why do we use other people's notes in modern times? Is there any historical reason?

There are five tones and seven tones in ancient times. This "sound" is roughly equivalent to today's scale. Five tones are five scales: Palace, Upper, Cross, Right and Yu. About 1, 2, 3, 4, 5, 6 in modern music notation. Later, two changes were added, namely palace change and signing change. Palace change is similar to "7" in modern music score, and turn sign is similar to "4" in modern music score. There is no sound equivalent to "4" in China traditional music. Five tones plus two tone sandhi are called "seven tones" or "seven tones", thus forming a seven-tone scale: Gong (1), Shang (2), Jiao (3), Bian (4), Qian (5), Yu (6) and Bian Gong (7).

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