There are phrases that are composed by 4 Chinese characters in Japan. It is called "Yojijukugo". It is one of idioms. We sometimes use Yojijukugo in our conversation. It is very useful to express and explain situation or a precept easily. People who use Yojijukugo make an intellectual impression for other people.
I especially like Ichi-go Ichi-e in Yojijukugo. I looked over it in dictionary and I knew that the word is derived from Japanese tea ceremony, Sado. We meet a lot of people every day and experience various situations. However, the event might be one chance and we would not be able to meet them again. This means "Ichi-go Ichi-e" and we must appreciate the moment that we meet them any time.
Since there are a lot of Yojijukugo, it is hard to learn Yojijukugo and use them in an instant for even Japanese people. Japanese are very complex and it might be difficult to learn Japanese. However, it will be more interesting to know Yojijukugo for people who learn Japanese.