Aimite wa wakaruru koto no nakariseba katsugatsu mono wa omowazaramashi - Yamato Monogatari(English Translation & Meaning)

あひ見ては別るることのなかりせば
かつがつものは思はざらまし

Roma-ji: Aimite wa wakaruru koto no nakariseba katsugatsu mono wa omowazaramashi
English Translation: If it were not that
meeting must be followed by
parting, I would not
be brooding over this and
that, half of one thing, half another
Meaning: If it were not that meeting must be followed by parting, I would not be brooding over this and that.
Commentary: 122 Half and Half

When Toshiko went on pilgrimage to Shiga temple she met a priest called Zōki and spent a night with him. They took a room in the bridge pavilion and made all manner of promises to each other. As she was leaving, word came from Zōki: "Aimite wa wakaruru koto no nakariseba katsugatsu mono wa omowazaramashi". Toshiko's reply was "Ikanareba katsugatsu mono o omouramu nagori mo naku zo ware wa kanashiki". That is the whole of the section.
Toshiko was the wife of Fujiwara no Chikane; she is entrusted with the offerings in the third section, composes a poem of condolence in the ninth, and dies in the thirteenth. She is one of the four gathered in the forty-first section and has poems in the sixty-sixth through sixty-eighth. Zōki was a priest, who appears again in the hundred and twenty-third section. Shiga temple stood in Ōmi province.
The setting is the bridge pavilion at Shiga temple, after a night together and many promises.
What prompted the poem was her setting out for home. It came from Zōki.
She answered with a poem of her own, and the exchange closes the section. This poem was later included in the Gosen-shū, attributed to an unknown hand.

The opening puts meeting and parting together as one thing: a meeting always brings a parting with it.
What follows is a condition contrary to fact, which takes for granted that parting does come.
The word in the fourth line means this and that, a certain amount — brooding of a moderate sort.
The closing says he would not be brooding at all. No meeting, no parting, no brooding. It is a poem sent after a night together, and what it does is regret the meeting — and that word for moderate brooding is exactly what her reply will fasten on.
Source: Yamato Monogatari
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