classic waka stream

現とも夢ともえこそ分きはてね
いづれの時をいづれとかせん
Roma-ji

Utsutsu to mo yume to mo e koso wakihatene izure no toki o izure to ka sen

English Translation
Whether it is real
or whether it is a dream
I cannot tell apart:
which of all the times I know
shall I call which?
Meaning
I cannot tell at all whether this world is waking or a dream. Which moments should I call real, and which a dream?
Commentary
Book Nine Poems of Lament 551

Headnote: "Composed by His Majesty on the frailty of the world"
Composed by the retired emperor on the frailty of the world. I cannot fully tell what is real from what is a dream, he says; which time should I call which? Faced with the uncertainty of life and death, he expresses the feeling of impermanence that even the present moment of living cannot be fixed as waking or dream, through the repetition of "izure," "which."
The author, "His Majesty Kazan-in," indicates a poem by Retired Emperor Kazan, the first son of Emperor Reizei and the sixty-fifth emperor. In 986, at nineteen, he took the tonsure and abdicated, and traveled to sacred sites in the provinces. He is also said to have been involved in compiling the Shūi Wakashū.
Poem 567 of this book by Jōtōmon'in also opens with "utsutsu to mo," saying that she cannot tell whether her days with the late Emperor Ichijō were dream or reality, and echoes this poem.

First line, "utsutsu to mo": "whether as reality," paired with "yume to mo" in the second line. Poem 567 of this book opens with the same words.
Second line, "yume to mo e koso": "e" with a negative expresses impossibility, and the emphatic "koso" closes with the perfective "ne" in the third line.
Third line, "wakihatene": "waki" is to distinguish, "hate" to do completely, and "ne" the perfective of the negative "zu," "I cannot tell them apart." The poem pauses here.
Fourth line, "izure no toki o": "which time."
Fifth line, "izure to ka sen": the interrogative "ka" closes with the attributive "sen," "which shall I call it?" Repeating "izure" in the fourth and fifth lines deepens the uncertainty between waking and dream.
Author
Retired Emperor Kazan
Source
Senzai Wakashu
Prev Poem
Omoikane kinō no sora o nagamureba sore ka to miyuru kumo dani mo nashi
Next Poem
Sakurabana miru ni mo kanashi nakanaka ni kotoshi no haru wa sakazu zo aramashi