Asukagawa shigarami watashi sekamaseba nagaruru mizu mo nodo ni ka aramashi

明日香川しがらみ渡し塞かませば
流るる水ものどにかあらまし

Roma-ji: Asukagawa shigarami watashi sekamaseba nagaruru mizu mo nodo ni ka aramashi
English Translation: Across the Asuka,
had I set a weir of stakes
to hold back its flow,
the water rushing onward—
would it have lingered calm?
Meaning: Had I stretched a weir across the Asuka River to hold back its current, would even the rushing water have lingered, calm and still?
Commentary: Book Two Elegies 197

Headnote continued from the preceding poem: "Poems composed by Kakinomoto no Asomi Hitomaro at the time of the temporary enshrinement of Princess Asuka at Kinoe, two short poems"
He wonders whether, had a weir been set across the Asuka River, even its rushing water might have stayed calm, entrusting to the river that shares her name his grief at failing to hold back the princess's life.
These are elegies Kakinomoto no Hitomaro composed when the body of Princess Asuka lay in state at the temporary shrine at Kinoe, with two short poems appended to the long poem 196. Princess Asuka was a daughter of Emperor Tenji, said to have been a consort of Prince Osakabe, and she died in the fourth year of Emperor Monmu's reign (700). This is the first of those two short poems.
The author, Kakinomoto no Hitomaro, was a court poet active in the reigns of Empress Jitō and Emperor Monmu. A master of the long poem and the elegy, he is the representative poet of the Man'yōshū and was later revered as the Saint of Poetry.
A note records a variant giving the final line as "mizu no yodo ni ka aramashi." Here the main text is followed.

The first line, "asukagawa," is the river bearing the same name as Princess Asuka; the next poem, 198, begins with the same line.
In the second line, "shigarami watashi," shigarami is a weir of stakes woven with brushwood or bamboo to hold back a river.
In the third line, "sekamaseba," mase is the irrealis of the counterfactual mashi, and mase ba ... mashi means "had I dammed it."
The fourth line, "nagaruru mizu mo," means "even the flowing water," overlaid with the passing life of the princess.
In the final line, "nodo ni ka aramashi," nodo means calm, and ka is an interrogative binding particle concluding in the attributive mashi: would it have stayed calm?
Author: Kakinomoto no Hitomaro
Source: Manyoshu
Prev Poem: Shikitae no sode kaeshi kimi tamadare no ochino sugiyuku mata mo awame ya mo
Next Poem: Asukagawa asu dani mimu to omoe ya mo waga ōkimi no mina wasure senu