Why do Japanese people use three different characters: kanji, hiragana, and katakata?

Why do Japanese people still use Chinese characters borrowed from China? I received this question from a good friend of mine. This is a very good question. Why do we use Kanji and Katakana together when we have an independent system called Hiragana? From the point of view of a learner of Japanese, one would think that it would be much easier to master Japanese if only hiragana was used. First, let’s talk about the history of kanji. Kanji was invented about 3300 years ago during the Shang Dynasty in China. It was a phonetic script called the Kou bone script. Korea, Vietnam, and the Ryukyu Kingdom imported Chinese characters from China and used them for a long time due to their tribute to China. In Japan, Chinese characters were introduced from China in the 1st century BC. Chinese copper coins from that period have been unearthed in Nagasaki Prefecture, and they have Chinese characters written on them. However, this does not mean that the Japanese of that time understood Chinese characters, because they m