Asukagawa shita nigoreru o shirazu shite senana to futari sanete kuyashimo

あすか川下濁れるを知らずして
背ななと二人さ寝て悔しも

Roma-ji: Asukagawa shita nigoreru o shirazu shite senana to futari sanete kuyashimo
English Translation: The Asuka River—
not knowing that beneath the surface
its waters ran so murky,
I lay with that man of mine,
and how bitterly I rue it.
Meaning: Not knowing that the Asuka River ran muddy underneath, I lay with him, the two of us—how bitterly I regret it.
Commentary: Book Fourteen Azuma Poems 3544

Headnote continued from the preceding poem: "Sōmon (Love Exchanges)"
As she did not notice the muddy depths beneath the Asuka River's surface, so she lay with a man without knowing the falseness of his heart, and she regrets it. The contrast between the clear-looking surface and the murky depths conveys the pain of a betrayed love.
It is one of the love exchanges. The Asuka River is thought by some to be the Asuka River of Yamato and by others a river in the east. The next poem also opens with "Asukagawa," so the two stand together.
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 name of a river; the next poem opens with the same line.
Second line, "shita nigoreru o": "Shita" is the riverbed and also the depths of the heart: the muddy bottom laid over his hidden falseness.
Third line, "shirazu shite": "Without knowing."
Fourth line, "senana to futari": "Senana" is an eastern endearment for a lover.
Final line, "sanete kuyashimo": "I regret having slept with him," with "mo" exclamatory.
Source: Manyoshu
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