Poems of Meng Jiao
Who speaks of Green Mountain injustice
Preserves the green pine's integrity.
Who speaks of Muddy River corruption
Preserves the full moon's face.
I have a pine-moon heart
That gallops through hardship untroubled.
But loyal and pure as I am
Destruction could still find me.
The title 寓言 means "fable" or "metaphor" or, poetically, "conceit." So I am assuming each of the poem's nouns points to something going on at the time. The An Lushan rebellion came and went while Meng Jiao was a child. But the Tang remained unstable afterwards, shored-up momentarily by this or that rare competent emperor. We have seen 松直 (pine straight) before once or twice. Perhaps it is a kind of code for some prominent person of the time. Then 明月 would be another one. And Meng Jiao, with his 松明 heart, identifies with both of them.
That he talks of destruction suggests that these two persons are on the wrong side of some imperial faction struggle. Bai Juyi married into a family of Yangs that were often on the wrong side. He became adept at keeping a low profile. All of this makes me think that the collators have plonked this poem into the wrong place. Scroll-wise, we are in Meng Jiao's late twenties - early thirties. And if talking politics is dangerous, he's not a wanderer any more. He's an over-forty official.
I am ignorant of too much in this poem for comfort. Although, there is another possibilty here as well. It is possible that this poem has simply fallen out of our reach, as far as translation is concerned. All of my guesses could be wrong. But we could be too far away now, historically and linguistically, to correct them.