Asukagawa seku to shiriseba amata yo mo inete komashi o seku to shiriseba

あすか川堰くと知りせばあまた夜も
率寝て来ましを堰くと知りせば

Roma-ji: Asukagawa seku to shiriseba amata yo mo inete komashi o seku to shiriseba
English Translation: The Asuka River—
had I known they'd dam it up,
many nights and more
I would have lain there by her side—
had I known they'd dam it up.
Meaning: Had I known they would dam the Asuka River—that they would part us—I would have slept with her night after night. Had I only known they would dam it.
Commentary: Book Fourteen Azuma Poems 3545

Headnote continued from the preceding poem: "Sōmon (Love Exchanges)"
Had he known beforehand that their love would be blocked like the Asuka River dammed, the singer would have lain with her many more nights. Repeating the same line in the second and last positions, he presses his regret.
It is one of the love exchanges and, following the preceding poem, begins with "Asukagawa." Where that poem regrets the lover's falseness, this one regrets their being torn apart.
The poet is unknown. The Azuma uta are thought to have been sung among the people of the eastern provinces, and they are marked by plain, open-hearted expression mixed with local dialect.

First line, "asukagawa": The same opening as the preceding poem, setting two Asuka River poems side by side.
Second line, "seku to shiriseba": "Seku" is to dam a river, overlaid with being kept apart; "seba" is a counterfactual condition.
Third line, "amata yo mo": "Many nights."
Fourth line, "inete komashi o": "Inu" is to take to bed, and "mashi" is counterfactual: I would have come having slept with her.
Final line, "seku to shiriseba": The second line is repeated as it is, deepening the regret.
Source: Manyoshu
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