Kono yūbe tsumi no saeda no nagarekoba yana wa utazute torazu ka mo aramu

この夕柘のさ枝の流れ来ば
梁は打たずて取らずかもあらむ

Roma-ji: Kono yūbe tsumi no saeda no nagarekoba yana wa utazute torazu ka mo aramu
English Translation: If this very eve
a sprig of the tsumi tree
should come floating down—
having set no weir to catch it,
might I let it slip away?
Meaning: If a branch of tsumi should come floating down this evening, having set no fish weir, would I let it pass by uncaught?
Commentary: Book Three Miscellaneous Poems 386

Headnote continued from the preceding poem: "Three poems on the immortal of the tsumi branch"
This is the second of the three poems on the immortal of the tsumi branch. Even if, like Umashine in the legend, a tsumi branch should float down this evening, he has set no weir, and so would fail to catch it—a witticism drawing on the legend. It can also be read as a playful lament for missing the chance to meet an immortal maiden. The left note says only "the above one poem," giving no author's name, so the author cannot be fixed.
The three poems on the immortal of the tsumi branch relate to the legend of Umashine, a fisherman of Yoshino, who picked up a branch of tsumi floating down the river; it turned into a beautiful immortal maiden, and the two became husband and wife.

First line "If this very eve" means this evening.
Second line "a sprig of the tsumi tree": tsumi is a kind of mountain mulberry, and sa is a prefix.
Third line "should come floating down": a condition.
Fourth line "having set no weir to catch it": yana is a weir of stakes for catching fish.
Fifth line "might I let it slip away": ka is interrogative and mu conjectural.
Source: Manyoshu
Prev Poem: Arare furi Kishimi ga take o sagashimi to kusa torikanawa imo ga te o toru
Next Poem: Inishie ni yana utsu hito no nakariseba koko ni mo aramashi tsumi no e wa mo