Yamakaze ni chiritsumu hana no nagarezu wa ikade shiramashi tani no shitamizu - Senzai Wakashu(English Translation & Meaning)

山風に散り積む花の流れずは
いかで知らまし谷の下水

Roma-ji: Yamakaze ni chiritsumu hana no nagarezu wa ikade shiramashi tani no shitamizu
English Translation: Had the blossoms piled
by the mountain wind not come
floating on the stream,
how would I have ever known
of the hidden valley brook?
Meaning: Had the blossoms scattered and piled up by the mountain wind not come floating down, how would I ever have known of the water flowing hidden in the depths of the valley?
Commentary: Book Two Spring Poems II 100

Headnote: "Composed on the topic 'Blossoms Floating on a Mountain Stream'"
Composed on the topic "Blossoms Floating on a Mountain Stream." Had the petals scattered and piled up by the mountain wind not come drifting down, how would the poet ever have known that water was flowing hidden beneath the plants of the valley? The conceit of learning of an unseen stream through the petals floating on it presents the discovery that falling blossoms reveal a hidden current.
The author, "Minister of the Left of Hanazono," is Minamoto no Arihito, son of Prince Sukehito, himself a son of Emperor Go-Sanjō. Adopted by Retired Emperor Shirakawa, he was given a surname and rose to Minister of the Left. He was called the Hanazono Minister of the Left after his residence at Hanazono, and excelled in poetry and music.

First line, "yamakaze ni": the wind from the mountains that scatters the blossoms.
Second line, "chiritsumu hana no": "of the blossoms that have fallen and piled up." "Hana mo hikazu mo tsumorinuru" in 77 and "chiritsumite" in 105 of this book also depict blossoms piling up as they fall.
Third line, "nagarezu wa": a negative hypothetical, "had they not flowed."
Fourth line, "ikade shiramashi": "ikade" is rhetorical and "mashi" counterfactual, answering "zu wa" in the third line: "how could I have known? I could not." The poem pauses here and is inverted with the last line.
Fifth line, "tani no shitamizu": ends on a noun, water flowing hidden beneath leaves and grasses in the valley. Where the preceding poem, 99, showed blossoms falling on a pond, this one shows them flowing down a mountain stream.
Author: Minamoto no Arihito
Source: Senzai Wakashu
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