Differences between old and new rhymes in metrical poems

Metric poetry is a poetic style transformed from the old physical rhythmic poetry. Take the old seven laws (seven words and four sentences in each sentence, requiring mutual parallelism and antithesis), five laws (eight words and five sentences in each sentence, requiring mutual parallelism and antithesis) and seven laws (eight words and seven sentences in each sentence, requiring mutual parallelism and antithesis). Writing the new rhyme "Seven Poems": The whole poem requires four sentences, each with seven words. There is no need to talk about levelness and duality in every sentence, but the first sentence should be leveled and the second sentence should be leveled from beginning to end. When writing a new rhyme five-step poem: the whole poem requires eight sentences, each with five words. There is no need to talk about parallelism and duality in every sentence. The first sentence should be flat and even, and the two sentences should rhyme flat and even. When writing new rhyme and seven rhymes: eight sentences in the whole poem, seven words in each sentence. There is no need to rhyme in every sentence, the middle four sentences do not need to be dual, and the upper and lower sentences do not need to be glued together. However, the first sentence is generally flat, and the two sentences are flat and rhyme to the end. When the above-mentioned old body rhyme is written into new rhyme, the general rhyme method is to use the first and second tones of the four tones of Putonghua as flat rhyme, while the old body rhyme rhymes with the ancient flat rhyme, so the new rhyme is called "new rhyme". That is to say, the new metrical poem is a reform of the old metrical poem, which only retains the characteristics of the whole number of poems, the number of words in each sentence and the rhyme of the first sentence (rhyming with ordinary pronunciation), while the rest of the old-style poems are abandoned because of strict requirements that the tone of each sentence should be opposite, insisting on the upper and lower sentences, and the middle four sentences should be dual (antithesis) and rhyming with the "flat tone" of the old rhyme book.