The Pingqian in ancient poetry is an important part of the rhythm of ancient Chinese poetry, which mainly involves the tonal collocation of words, in order to create the rhythmic beauty and quality of poetic language.
In ancient Chinese, Chinese characters were divided into four basic tones according to the tonal characteristics of pronunciation – ping, shang, go, and enter (modern Mandarin only retains the four tones of yin ping, yang ping, shang sheng, and go sound, of which the incoming sound has been merged into the other three tones).
Pingsheng: Corresponding to the first tone (Yinping) and the second tone (Yangping) in modern Mandarin, it usually refers to the tone of the sound that does not rise or fall or rises gently.
Voice: including the upper tone, the sound and the sound in ancient Chinese, corresponding to the modern Mandarin is mainly the third tone (upper tone) and the fourth tone (go to the voice), which is characterized by the pronunciation with ups and downs or short.
In the creation of poetry, the application of the law of flatness is to make the poem form a subdued and abrupt effect on the syllables, and increase the rhythmic beauty of the poem when reciting.
For example, the basic sentence structure of the seven-character poem "平平仄仄平仄", that is, each position of the poem is required to arrange the tone of the words according to the principle of alternating between the plain and the flat.
Strict near-style poems (such as rhythmic poems and quatrains) have clear rules for pingxuan, and the characters in different positions have different requirements for pingxuan, and at the same time, together with the rhyming rules, together form the basic framework of poetic rhythm. In ancient style poetry, although it is not necessary to strictly follow the law of Pingxuan, the use of Pingqian is still one of the important techniques to enhance the artistic effect of poetry.