Chūka jakuboku shishō 中華若木詩抄 ("Selection of Chinese and Japanese poetry") is a 16th-century-ish example of the shōmono 抄物 genre: books explaining classical or otherwise elevated literary works in the contemporary vocabulary. This shishō in particular is a sort of intro to Zen poetry for new initiates.

Number 218 in Ōtsuka Mitsunobu 大塚光信, Ozaki Yūjirō 尾崎雄二郎 and Asakura Hisashi 朝倉尚's 1995 edition for Iwanami Shoten is "Falling leaves" (落葉) by a 14th-century Rinzai monk from Tosa named Gidō Shūshin 義堂周信, and goes like this:

夜雨蕭々四五更
愁辺細聴至天明
開門試倚風前看
真个梧桐落葉声

The night is rainy — seu seu — into the early morn
Within the gloom I heard it all, and now the dawn is here
I open up the door, just to see what lies outside
The truth: the sound I heard was just the falling wutong leaves

Seu seu 蕭々 is, very conveniently, mimetic for lonely natural sounds and atmospheres in general, not just rain.

The bulk of the Chūka jakuboku shishō's commentary on this poem is about the fact that it contains its own title. Generally, we are told, it's better for this not to happen, although it's not so bad if it does. Better to use the title in the poem than to go to such tortuous lengths to avoid it that the poem itself suffers. On the other hand, if the characters of the title must be used in the poem, they should at least not appear together. Or maybe it's okay for them to appear like that if it's at the start of the first line, because after all that's how the Classic of Poetry is presented, and Du Fu was prone to this editorial technique too. But in this poem it appears in the fourth line! But this is an old (上古) poem, from the days before Jueju were "beautifully ordered". All in all, today's students should be wary of following its example too blindly.

(The editors of the Iwanami edition observe in a footnote that the schizophrenic back-and-forth in this passage looks like multiple editors arguing with each other, but the text itself does not delineate different voices.)

Incidentally, according to the Nihon Kokugo Daijiten, the jakuboku 若木 in the title of this book originally (i.e. in Chinese) referred to a mythical tree at the westernmost extremity of the Earth, behind which the sun set. How did this come to mean "Japan"? Simple confusion with fusō 扶桑, a mythical tree at the easternmost extremity of the Earth, which had a much more logical association with Japan.