Yamamori no arikeru shira ni sono yama ni shime yuitatete yui no haji shitsu

山守のありける知らにその山に
標結ひ立てて結ひの恥しつ

Roma-ji: Yamamori no arikeru shira ni sono yama ni shime yuitatete yui no haji shitsu
English Translation: That a mountain guard
was already there, not knowing,
on that mountain there
I put up a marking rope—
and now I am put to shame.
Meaning: Not knowing that the mountain already had a keeper, I tied my marking rope upon it—and now I am shamed for having tied it.
Commentary: Book Three Allegorical Poems 401

Headnote: "A poem recited by Lady Ōtomo no Sakanoue on a day of banqueting with her kin"
This poem belongs to the section of Allegorical Poems in Book Three. It was recited at a banquet for her relatives. Not knowing that the mountain already had a keeper, she set up a marking rope to claim it and was put to shame. Read as an allegory with the mountain as a man, it jokingly tells how the man she had in mind as a son-in-law turned out to have a partner already. In the next poem, Ōtomo no Surugamaro replies.
The poet, Lady Ōtomo no Sakanoue, was a daughter of Ōtomo no Yasumaro, half-sister of Ōtomo no Tabito, and aunt of Ōtomo no Yakamochi. As mistress of the Ōtomo household she supported the clan, and she left many poems in the Man'yōshū.

First line "That a mountain guard": yamamori is a mountain keeper, here the man's existing partner.
Second line "was already there, not knowing": shira ni means "without knowing."
Third line "on that mountain there" stands for the man she had set her eye on.
Fourth line "I put up a marking rope" shows her attempt to claim him.
Fifth line "and now I am put to shame": tsu is perfective. Repeating yui ("tying") from the fourth line, it ends in playful self-mockery.
Author: Lady Ōtomo no Sakanoue
Source: Manyoshu
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