The metrical poems in the Tang Dynasty, that is, the flat tones in metrical poems, are based on the rhyming system that began in the Sui Dynasty. This system has been used from Sui and Tang Dynasties to modern times. Tang rhyme in the Tang Dynasty, Guang Yun in the Song Dynasty, Ji rhyme, Pingsheng rhyme and so on come down in one continuous line and have always been officially recognized as orthodoxy.
Qieyun is no longer visible today, but the official rhyme of Tang and Song Dynasties can be regarded as the same strain. The reason why the government has to stipulate the standard of four tones and rhymes is because metrical poems and rhymes are often called compulsory subjects in the imperial examination system.
Therefore, it can be said that the level tones in the Tang Dynasty's metrical poems are all based on the rhyme cutting in the Sui Dynasty, and the rhyme cutting is naturally a system based on balancing dialects in many regions. The expression of cutting rhyme set a standard for poetry after Sui and Tang Dynasties.
For example, Qian Qi in the Tang Dynasty tried to paste the poem "Xianggulingse"
It is often heard that the immortals in Xiangshui are good at playing the piano and singing. Beautiful music makes Feng, the river god, dance and dance, which is unbearable for travelers who travel far away. Deep and sad melody, even hard stones are moved by sadness; The sonorous, high-pitched musical tone is so penetrating that it has been flying to lofty places. Cangwu complains, and Angelica dahurica is fragrant. Music flows along the water to Xiangjiang River, and then into the lake, flying over the vast Dongting Lake. The music is quiet, but there is no drums of the water god. The river disappears, revealing several peaks, which are green and charming.
According to the standard of rhyme books in Tang Dynasty, if winter and east are mixed, the mixed dishes of green and Geng belong to rhyme. Qian Qi's poems are all green rhymes, not mixed with Geng rhymes.
The flatness and rhyme of metrical poems are different from the language in life. Beginners and writers in the Qing Dynasty said in the Preface of Tang People's Trial Sticking: "Poetry has a beginning, and today's poetry is not elegant, nor is it the so-called Yuefu ancient style in the Han, Wei and Six Dynasties.
The law is designed for trial. Before the Tang Dynasty, there were so-called four rhymes, six rhymes and eight rhymes in poetry, but they were all tried out. Before the Tang Dynasty, poetry was not limited to three-tone, four-tone, thirty-tone, and one hundred-seven-tone, but only for trial use. It's what I did today. It's also dharma and poetry review.
As an examination tool, metrical poetry must be determined in strict accordance with rhyme books. Even though the pronunciation of rhyme books is gradually different from that of life, poets still use official rhyme instead of life pronunciation when writing poems and selecting officials.
Rhyme books compiled by people in Sui and Tang Dynasties are precious wealth for our language research. Because poets have been writing poems in strict accordance with rhyme for thousands of years, it is easier for us to understand the poems after Qi and Liang Dynasties today. Today's poems mostly rhyme in a few days. Even if it doesn't rhyme, evidence can be found, because the official rhyme sets a yardstick for the inheritance of Chinese language.