Bai's "Late night" is a single sentence, and it manages to turn one of our oldest assumptions upside down. Darkness, for most of us, means loss: the lights go out, the world disappears, and we lose the use of our eyes. Bai says the reverse. The darkness is "filled with wonderful things," and the only people who miss them are those who have gone to bed.
The title does a lot of quiet work. "Late night" sets the scene before the poem begins, and it tells us something about the speaker, who is awake at an hour when most people are not. Nothing else is said about where they are or why they can't sleep. The poem doesn't explain, and that restraint is part of its charm. We are left to picture a window, perhaps, or a dark room, and someone sitting in it looking out.
The central image is the verb "filled." Darkness is usually described as an absence, an emptiness where the day used to be. Here it becomes a container, something with a full inside, like a cupboard or a pond or a pocket. The vocabulary of "emptiness" quietly flips into the vocabulary of "abundance." And what it holds is "wonderful things," which is a deliberately vague phrase. Bai doesn't name stars, moths, moonlight or secrets. The word "things" is almost shrugging, as if the speaker could list them but would rather not spoil them. That vagueness is generous, because every reader fills the darkness with their own wonders. It also suggests that what the speaker sees may be hard to put into words.
The second half of the sentence introduces a contrast. "People who sleep" is a slightly distant phrase. It isn't "we" or "you," just a general crowd, and the speaker stands outside it. Depending on how you hear it, the tone could be gently superior, a little sorry for the sleepers, or simply awestruck, the way someone sounds who has found a secret and can't help mentioning it. The poem leaves that open. There is an irony in "cannot see" as well. We expect darkness to be the thing that blocks sight, yet here the blockage belongs to the sleepers' closed eyes, not to the night. The darkness is not hiding anything. The sleepers simply aren't looking.
The sound of the line supports this. There is no rhyme, and the rhythm is loose, roughly four beats in the first half ("The DARKness is FILLED with WONderful THINGS") and a shorter, more settled run in the second. The comma after "things" works like a small held breath before the second half arrives. The line also leans on soft s-sounds: "darkness," "is," "things," "people," "sleep," "cannot see." Together they give the sentence a hush, as though it were being spoken at the volume suited to a sleeping house. The poem ends on "see," a long, open vowel, so the last thing we hear is the act of seeing, in a poem about darkness.
It helps to notice how little the poem contains: no named objects, no description, no argument. Yet the single sentence has a clear shape. It starts with a surprising claim, then adds a reason why most people don't know it. That is nearly the structure of a small story, with a discovery and a reason it stays hidden, compressed into a breath.
What makes "Late night" worth reading is the way it changes the value of something ordinary. It doesn't tell us that night is beautiful. It suggests that attention is what makes it so, and that being awake, in the sense of being truly alert to the world, might matter more than the hour on the clock. The poem is also a mild dare. After reading it, anyone who has been lying awake and resenting the dark may look at it differently, and wonder what they have been too tired, or too annoyed, to notice.