classic waka stream

たつた川もみぢ葉流る神なびの
みむろの山にしぐれ降るらし
Roma-ji

Tatsutagawa momijiba nagaru kannabi no Mimuro no yama ni shigure fururashi

English Translation
Down the Tatsuta
the autumn leaves are floating —
then on the sacred
hill of Mimuro, it seems
the cold rains must be falling
Meaning
Down the Tatsuta the autumn leaves are floating; so on the sacred hill of Mimuro the cold rains must be falling.
Commentary
151 The Tatsuta River

The same emperor at Nara, looking at the fine autumn leaves on the Tatsuta river, heard Kakinomoto no Hitomaro compose "Tatsutagawa momijiba nagaru kannabi no Mimuro no yama ni shigure fururashi", and himself composed "Tatsutagawa momiji midarete nagarumeri wataraba nishiki naka ya taenamu". That is the whole of the section.
The emperor at Nara is the emperor of the Nara capital, who appears in the hundred and fiftieth section. Kakinomoto no Hitomaro is the great poet of the Man'yō-shū, who composes at the Sarusawa pond in that section. The Tatsuta river flows through Yamato and was famous for its autumn leaves; the sacred hill of Mimuro stands above it.
The setting is the Tatsuta river, with the leaves at their finest.
What prompted the poem was the emperor's looking at them.
He answered it, and the section closes with the two poems. This one was later included in the Kokin-shū and the Shūi-shū.

The opening states plainly what is in front of him: leaves floating down the Tatsuta.
The sacred hill of Mimuro is where a god is held to dwell; it lies upstream, and is where the leaves come from.
The closing infers that the cold rains are falling there, in a grammar of inference from evidence.
From what can be seen downstream he reasons to what cannot be seen upstream. Telling of the unseen by way of the seen is the frame of the whole poem.
Source
Yamato Monogatari
Other