I see that the prefix of the word "Qi" in many copybooks is oblique, and the prefix of the word "Rui" is also oblique, but why write it obliquely?

Because the word "mountain" is similar to the words "Qi, Duan and Rui", especially in the running script, every time we see the word "mountain" as one of the components of a word, or the upper end or the upper right end, and most of them are running scripts, the word "mountain" is usually written obliquely at this time.

Reason:

First, the word "mountain" is written too correctly, and its three vertical paintings are concentrated in the same position, which may have the disadvantages of being positive and monotonous.

Second, the running script emphasizes the dynamic trend, while the dignified word "mountain" cannot be moved, which does not meet the requirements of running script.

Third, calligraphy pays attention to charm. The powerful running script pays attention to the avoidance and echo between the upper and lower words and between the left and right lines.

Imagine that if the word "mountain" of "Qi, Duan and Rui" appears in a certain part of the running script, if it is not handled dynamically, this branch will be very eye-catching and uncoordinated. So it will affect the artistic level of the whole article.