classic waka stream

even in ages of gods
never once has it been heard—
the Tatsuta River
binding its flowing waters
in deep-dyed scarlet

Meaning
Even in the age of the gods, it has never been heard that the Tatsuta River could bind its waters in deep scarlet dye.
Commentary
Book Five Autumn Poems (Part Two)

A poem also included in the Hyakunin Isshu.

It expresses that even in the age of the gods—an age of fierce and wondrous happenings—such a thing as the Tatsuta River dyeing its waters deep crimson has never been heard of.

It is a heightened expression of the beauty of autumn leaves scattered upon the Tatsuta River (in present-day Ikaruga, Ikoma District, Nara), a place famed for its autumn colors.

“Chihayaburu” is a pillow word applied to “gods,” carrying a sense of wild or awe-inspiring power.
Author
Ariwara no Narihira
Source
Kokin Wakashu
Other