Why are there so many four-character idioms? This is probably because four words are easier to grasp. For example, China's ancient poetry collection "The Book of Songs" consists of four sentences, and the ancient history "Shangshu" also has some four sentences. Later, beginners read three-character classics, hundreds of surnames and thousands of words, the latter two of which are four sentences. The first, second and third episodes of Four-eyed Miscellaneous Son and Long Wen Whip Shadow are all four words. Although this is a sermon, it shows that these four words are loved and recited by people.
As I said before, idioms are mostly composed of four words, and the few are less than four words or more than four words; Especially there are even fewer idioms with less than four words. Therefore, when the Japanese speak Chinese, there is a saying of "four-character Chinese" (see Modern Middle School Putonghua edited by Yoshida Mori, 1978 edition), and some of them are also called "four-character idioms" (see Middle School Putonghua edited by Quan Zhongzhi, 1978 edition). But some of the idioms they listed in Four-character Chinese and Four-character Idioms are not what we call idioms, because we don't have that kind of statement. Such as "from left to right", "semantic", "hesitation in execution" and "question and answer". For another example, they also regard "spring, summer, autumn and winter", "front, back, left and right" and "east, west, north and south" as "four-character idioms", and we disagree. "Spring, summer, autumn and winter" is a meteorological term, "front, back, left and right" is a common orientation term in daily life, and "east, west, north and south" is a common orientation term in geography.
However, it is undeniable that idioms have four obvious characteristics. For example, the following idioms are not four words in terms of their origin. In other words, these idioms are all four-character idioms refined from non-four-character idioms. Try to look at the relationship between the following idioms and their origins:
(1) Be observant: "Be observant, not pay." (The first part of Mencius Liang Shang)
(2) Seek fish by the edge of the wood: "Seek it by the line and seek fish by the edge of the wood." (The first part of Mencius Liang Shang)
(3) Get twice the result with half the effort: "At present, the benevolent government of Wancheng is enjoyed by the people. People with semi-ancient stories will do twice as much, but that's the truth. " (Mencius, Gong Sunchou, Part I)
(4) Carving a boat for a sword: "The Chu people waded into the river, and the sword fell into the water from the boat. Carving a boat: that's where my sword fell. The ship stopped at the destination, and the Chu people jumped into the water from the marked place to find the sword. The boat did it, but the sword couldn't. Wouldn't you be puzzled if you asked about the sword? " ("Lv Chunqiu Cha Jin")
(5) Donkey skill is poor: Liu Zongyuan wrote a "Three Commandments" in the Tang Dynasty, and one of the subtitle is "Donkey of Money". "I'm at the end of my wit" is taken from the story described in this article.
(6) A broom is worth 1,000 yuan: (or "A broom cherishes yourself") "China people say that if you have a broom at home, you will enjoy 1,000 yuan, but you will never see it yourself." (Cao Pi's Dian Lun Paper)
From the above, the four words of idioms are very obvious. Or we can reduce words with more than four words to four words, such as "seeing through autumn" and "seeking fish from the edge of trees", or merge two sentences into one sentence with only four words, such as "getting twice the result with half the effort" and "Our daughter is precious". Or write a multi-word story into four words and become idioms, such as "carving a boat for a sword" and "the donkey is poor in skills"
Some words of the ancients could have been aphorisms and idioms. Just because it was more troublesome to change it to four words, I had to give it up and use it as a guide. For example, Fan Zhongyan's "The Story of Yueyang Tower in Song Dynasty" has a good moral, which means "Worry about the world first, and then enjoy the world." However, due to the large number of words, idioms cannot be formed. We can only regard them as epigrams and sometimes introduce them into articles. However, if "no pains come", it is easy to say and remember, so it can become an idiom. The phrase "all wastes flourish" in Yueyang Tower has become an idiom because it is four words.