Is Li Shangyin's untitled poem (with a heart in mind) a regular poem or an ancient poem?

This poem is a metrical poem.

The so-called classical poetry is based on classical poetry, which has no certain standards and is not bound by metrical rules. Any poem that is not bound by metrical rules is called archaic poetry, such as The Book of Songs.

Rhyme is a kind of poem that pays great attention to rhyme, uniformity and antithesis. Its meter is very strict, so it is called rhyme. Rhyme generally has these four characteristics:

Each song is limited to eight sentences, forty words in five laws and fifty-six words in seven laws.

Lower the rhyme

Every level is regular.

There must be confrontation, and the position of confrontation is also stipulated.

The quatrains are five-character quatrains and seven-character quatrains, and the number of words is half less than that of metrical poems, and they are limited to four sentences. It can be divided into two categories: ancient absolutes and legal absolutes. The ancient quatrains are not bound by the flat law, and the metrical quatrains should be both flat rhyme and flat law, which is equivalent to half a poem.