When ancient calligraphers wrote the word "day" and the word "Yue", they basically wrote the word "day" wider than now, and the word "Yue" was basically written like this, so basically they couldn't see the relationship between being fat and thin. What's the difference? It is the sealing and unsealing of this upper left part.
We see such words in ancient inscriptions, as long as they are not printed in the upper left corner, they are the word "Yue" and the word "Japan". Because it has the meaning of philology.
The word "Yue" cannot be sealed. There is a gap in the writing place of Japanese characters. Because we talk with our mouths open, it can't be tightly closed together, so this leaves a mouth, which is not sealed.
And this word "day", its original hieroglyph is a point in a circle. From a pictographic point of view, the sun has no gap. It's not like the moon. So there is no gap in the word "day".
The above is the difference between these two words. Of course, it is not so strict in running script and cursive script. But when we write regular script, we should make it clear that regular script is standardized and can't be written casually.
say
Yue, a common Chinese word (first-class word), is pronounced Yu and refers to things, which was first seen in Oracle Bone Inscriptions in Shang Dynasty. The original intention is this; Extend to be called; Turn into mood auxiliary words.
Etymological evolution
Yue, the word refers to things. Add a short cross at the beginning of the text to indicate that the words come from the mouth.
In Oracle Bone Inscriptions in the early Shang Dynasty, the word "moon" was used to indicate that the short cross was located in the center of the upper part of the word "mouth". Judging from the Oracle bone inscriptions in the late Yin and Shang Dynasties, this short cross moved parallel to the right and connected with the higher part of the right boundary of the "Kou" shape, which was inherited by Oracle Bone Inscriptions and the Western Zhou Dynasty in the previous generation.
By the spring and autumn period, the left end of the short cross was bent upward, and after the Warring States period, it was spread to Biography, saying that it was "like a breath." From the end of the Warring States Period to the Qin Dynasty, the characters of the State of Qin were all horizontally sealed and easily confused with the word "gan". By the Eastern Han Dynasty, there were two main ways of writing: one was to inherit the old style for two weeks, and the left side was not sealed; The second type is top horizontal printing, which is similar to the word "day", but the difference with the word "day" is only flat width.
Later regular script inherited the second form. The original meaning is. It is extended to address and reduced to mood auxiliary words.