Do you have to rhyme when writing poetry?

I don't think so. The expression of the most important meaning of poetry, "writing poetry should not only have content, but also rhyme", which changes the focus. Someone asked Chairman Mao how to write a good poem, and his old man said; "Poetry expresses ambition", especially modern poetry, does not need so many rhymes, because previous poems were sung with songs, and rhymes are more acceptable to read.