What are the most difficult poems in ancient China? A poem written in a very obscure way.

It should belong to Li Shangyin's untitled Misty Poetry in Tang Dynasty.

For example, Unnamed Time was a long time before I met her, but it was even longer after we separated. The unnamed stars and the wind last night, Jinse and so on. These poems are neither titled nor vague. What's more, the author did not leave a few explanations about these poems in any writings and handed down materials. It may be that these poems are only written for yourself and appreciated by yourself, and there is no need to let others know.

At that time and now, most people think that they wrote about love, such as "the silkworm in spring will weave until it dies", "However, I feel the harmonious heartbeat of the sacred unicorn" and "a moment that should last forever". However, for more than a thousand years, there have been different voices that the author has concealed many of his emotional expressions, and there is no consensus.