Takaterasu waga hi no miko no imashiseba shima no mikado wa arezu aramashi o

高照らす我が日の御子のいましせば
島の御門は荒れずあらましを

Roma-ji: Takaterasu waga hi no miko no imashiseba shima no mikado wa arezu aramashi o
English Translation: If our sun-bright prince,
shining high above us all,
were still with us here,
the Shima Palace gates
would not have fallen to ruin.
Meaning: If our high-shining prince, child of the sun, were still alive, the halls of the Shima Palace would not be falling into ruin.
Commentary: Book Two Elegies 173

Headnote continued from the preceding poem: "Twenty-three poems composed in grief by the attendants of the Prince's palace"
Before the palace that has begun to decay, the speaker laments that had the prince lived, the halls of the Shima Palace would never have fallen into ruin.
According to the headnote, these are twenty-three poems composed in grief by the attendants who served in Prince Kusakabe's palace. A left note, citing the Nihon shoki, records that the prince died in the fourth month of the third year of Empress Jitō's reign (689). The sequence takes up, scene by scene, the laments of the attendants: the garden and ponds of the Shima Palace bereft of their master, and the night watches they kept on the hills of Mayumi and Sada where the prince lay in state. This is the third poem of the sequence.
The authors were the attendants who served in Prince Kusakabe's palace, and their individual names have not come down to us. Toneri were officials who served close to the Emperor and members of the imperial family as guards and aides. One theory holds that Kakinomoto no Hitomaro composed the poems in the attendants' voice, but this is not settled.

The first line, "takaterasu," is a pillow word for hi, the same first line as the first poem of the sequence, 171.
The second line, "waga hi no miko no," is also the same as in 171 and refers to Prince Kusakabe.
In the third line, "imashiseba," imasu is an honorific for "to be" and se is the irrealis of the past ki, forming a counterfactual with mashi: had he been alive.
The fourth line, "shima no mikado wa," means "the palace halls of Shima." It corresponds to "miko no mikado" in 168 by Kakinomoto no Hitomaro in this book.
The final line, "arezu aramashi o," means "would not have fallen to ruin," as if answering "aremaku oshi mo" in 168 with grief at the palace's decay.
Source: Manyoshu
Prev Poem: Shima no miya ue no ike naru hanachidori arabi na yuki so kimi masazu tomo
Next Poem: Yoso ni mishi mayumi no oka mo kimi maseba tokotsu mikado to tonoi suru kamo