The title does half the work here. Nothing in the four lines mentions a factory, a machine or a chimney, yet once we read "Industrial revolution" above them, every image turns toward that meaning. The poem will not call this period progress. It calls it war, and it says the war "comes from the east", the direction of sunrise. Judging by that choice, the new age arrives like a dawn that is also an invasion, bright on the horizon and hostile on approach.
The second line is the poem's strangest and most memorable: "black like the bird who takes sad children." The simile slides around. It is not clear whether "black" describes the war, the bird, or the whole scene, and the poem never says what kind of bird it is. The bird is also given a will, because it is someone "who takes". Most of us know the folk image of a stork delivering babies, and here the bird has reversed the job, carrying children away instead of bringing them. The word "sad" is blunt and almost childlike, with no elaboration. The children are already unhappy before they are taken, so the taking feels less like a shock than like something long expected. Readers may think of children drawn into factory work, but the poem leaves that to us and only supplies the dark shape and the loss.
The second couplet moves from the countryside of myth into the city: "the city conquered play." With no punctuation, the grammar is easy to read two ways, but the most natural reading makes the city the conqueror and play its territory. The verb "conquered" carries the war of line one forward, so the city becomes the first captured ground. What falls is not a treasure or a border but play, the smallest and most childlike thing. It also echoes "children" in the line above, so the victims and the loss sit side by side.
Then the poem turns to a person. After three lines about the world, "I" arrives, and it is the only capital letter in the body of the poem, small and late. "I have not lived but to fight" has an old-fashioned ring, and the "not… but" construction means "only", so the speaker has lived for nothing except fighting. It can also be heard as a bare statement, "I have not lived", with the fighting added as an afterthought. Either way, life and fighting are no longer separate. Notice too that all seven words of this line are single syllables, which makes it hammer like a drumbeat. The earlier lines carry softer, longer words such as "city", "conquered" and "children". If we read the speaker as one of those children grown up, that is an inference from the poem's structure, but the sequence from "sad children" to "play" to "I" invites it.
The form is spare. There is no rhyme, no punctuation and no capitals except that "I". The lines run to roughly five, nine, six and seven syllables, so the second line is stretched long and then drops away on the soft ending of "children". Sound does quiet work as well: the hard k sounds in "comes", "black", "takes" and "conquered" give the lines a clipped, percussive edge. Because nothing is punctuated, no line closes with a full stop, and the poem ends on "fight" with no sense of the fight being over.
What makes it significant is how much it refuses to say. A huge historical change is squeezed into one bird, one city and one voice, with no dates, numbers or arguments. The poem asks what a revolution costs and who pays, and its answer is the one thing that cannot be measured in output: a child's freedom to play. The final turn to "I" makes that cost personal, a whole life spent on a battlefield someone else declared.