classic waka stream

All the mountains now
Have moved here to gather today—
Surely it must be
To mourn the springtime parting
We bid to her this season.

Meaning
All the mountains seem to have moved here to gather today; surely it must be to mourn the parting of spring and the farewell to the lady.
Commentary
77. Mourning the Parting of Spring

There was an emperor known as the Emperor of Tamura (Emperor Montoku). A lady of the court named Takagiko, who was his consort, passed away. A memorial service was held at Anshō-ji, and many people brought offerings. The offerings were attached to the branches of trees and set up before the temple hall, so that it looked as though wooded mountains had moved and appeared there.

Fujiwara no Tsuneyuki, who was then the Captain of the Right Imperial Guards, came and, after the lecture on the sutra had ended, gathered people to compose poems with the theme of the memorial service held that day, asking them to make poems with a feeling of spring.
The poem was composed by an old man who was the Head of the Right Horse Guards, who mistook the offerings attached to the branches for real mountains.

A nyōgo was a high-ranking court lady who attended the emperor’s bedchamber, ranking below the empress and chūgū. Takagiko was the eldest daughter of Fujiwara no Yoshisuke, the Minister of the Right.
Anshō-ji is located in Yamashina in Kyoto Prefecture and was built at the wish of the Empress of Gojo.
The old man who was the Head of the Right Horse Guards was Ariwara no Narihira, who held this post from the age of forty-one to fifty-one.
Source
Ise Monogatari
Other