There is nothing in ancient Chinese poetry that does not rhyme. However, it was laborious and time-consuming for the ancients to learn "rhyme", which was far less easy than it is now. In ancient times, it was not easy to explain what "rhyme" was. Now, with the common Chinese phonetic alphabet, even primary school students can learn it thoroughly, which is convenient for explaining and mastering rhymes.
Chinese pinyin has initials and finals. A Chinese character is put together with phonetic symbols, generally with initials and finals, with the initials in front and the finals behind.
For example, Li Bai's poem "Send Baidicheng Early":
Bai Di Tsai Yun Jian (between the initials J and the vowel ian)
Jiangling is a thousand miles away, and it will be returned in one day (also, the initial h plus the vowel uan)
Apes on both sides of the strait can't stop crying (live, initial zh plus vowel U)
The canoe has passed Chung Shan Man (initial sh, vowel an).
The vowel alphabetical order of the last word of these four poems is ian, uan, u, an. The vowels in the first sentence, the second sentence and the fourth sentence are the same, but the third sentence is different. The so-called "rhyme" in poetry is roughly equal to the pronunciation of vowels in pinyin letters. Words with the same vowel sound are words with the same rhyme. Putting homophonic words in a certain position is "rhyme". It's called rhyme. The rhyme of the first, second and fourth sentences in Li Bai's poem is an, so it rhymes. The third sentence rhymes differently, so the third sentence doesn't rhyme. The quatrains stipulate that the third sentence cannot rhyme, so the rhyme of this poem is completely qualified.
The rhyming rule of ancient poems or modern poems is generally that every other sentence rhymes, that is, every other sentence must have the same vowel, that is, every double rhyme. No matter how many sentences, every double rhyme. As for the first sentence, it can rhyme or not. At the same time, rhyming and quatrains must rhyme to the end, and no rhyme can be changed in the middle; Long ancient forms allow the middle to change rhyme. For example, as long as there are dozens or a hundred rhymes in the ancient style, the poem is difficult to write. Rhyme and quatrains can only be changed with four rhymes or two rhymes.
Rhyme, with wide rhyme and not narrow rhyme. The so-called "wide rhyme" means that there are many words in the same vowel, which can have a wider range of choices; The so-called "narrow rhyme" means that there are few words with the same vowels and metrical poems are rarely used.
Rhyme can sometimes be changed. In metrical poems, especially in arrangement, it is really difficult to find a suitable homonym in order to express the meaning accurately, so it is allowed to bet on "adjacent rhymes". The so-called "adjacent rhyme" means using words with adjacent rhyme. This is a variant.