Yorozuyo o Mikami no yama no hibiku ni wa Yasukawa no mizu sumi zo ainikeru - Shui Wakashu(English Translation & Meaning)

万代をみかみの山の響くには
野洲河の水澄みぞあひにける

Roma-ji: Yorozuyo o Mikami no yama no hibiku ni wa Yasukawa no mizu sumi zo ainikeru
English Translation: Since on Mikami,
which sees ten thousand ages,
the glad voices ring,
the waters of Yasu River
all run clear in answer there.
Meaning: Since voices celebrating ten thousand ages ring out on Mount Mikami, the waters of the Yasu River have grown clear in answer.
Commentary: Book Ten Kagura Songs 603

Headnote continued from the preceding poem: "Fūzoku songs for the Great Thanksgiving Festival of the first year of Anna: Mount Mikami"
The poem says that since voices celebrating ten thousand ages ring out on Mount Mikami, the waters of the Yasu River flowing at its foot have grown clear in answer. Overlaying the celebratory voices echoing on the mountain with the clearing of the river's water, it depicts heaven and earth responding to the spirit of celebrating the reign. It is the third of the poems on Mount Mikami, and where the two preceding poems sang of the mountain's sakaki, it turns to the river at the mountain's foot.
The headnote, "Fūzoku songs for the Great Thanksgiving Festival of the first year of Anna," shows that the poem was offered at the Great Thanksgiving Festival held in the first year of Anna upon the accession of Emperor Reizei. At this festival, poems working in the place names of the provinces chosen as Yuki and Suki were offered, and from here to 608 poems follow whose topics are the names of mountains and shores in those provinces.
The author, written as "Motosuke," is Kiyohara no Motosuke. The father of Sei Shōnagon, he took part in compiling the Gosenshū as one of the Five Men of the Pear Chamber. He is counted among the Thirty-Six Immortal Poets.

First line, "yorozuyo o," means "ten thousand ages," beginning with the same word as the first line of the preceding poem, 602, "yorozuyo no."
Second line, "Mikami no yama no," appears to be a pivot word, with "mi" pivoting on "to see," laying "seeing ten thousand ages" over the place name Mount Mikami.
Third line, "hibiku ni wa," means "since they ring out," speaking of voices celebrating the reign echoing on the mountain.
Fourth line, "Yasukawa no mizu," means "the waters of the Yasu River," which flows at the foot of Mount Mikami.
Final line, "sumi zo ainikeru," means "have grown clear throughout," with the binding particle "zo" resolved by "keru," the attributive form of the past auxiliary "keri."
Author: Kiyohara no Motosuke
Source: Shui Wakashu
Prev Poem: Yorozuyo no iro mo kawaranu sakakiba wa Mikami no yama ni ouru narikeri
Next Poem: Mitsugi tsumu Ōkurayama wa tokiwa nite iro mo kawarazu yorozuyo zo hemu