Krebs passes time sitting on his porch and reading about the war, describing both the book and his time as a soldier in a positive, though ultimately ironic, manner:
He sat there on the porch reading a book on the war. It was a history and he was reading about all the engagements he had been in. It was the most interesting reading he had ever done. He wished there were more maps.... Now he was really learning about the war. He had been a good soldier. That made a difference.
The idea of a book on a war one fought in being the most interesting reading one has ever done, and more informative than fighting in the war itself, is unexpected and therefore situationally ironic. This notion is particularly surprising considering Krebs's disposition towards his time as a soldier. Although Krebs feels compelled to lie about his time as a soldier, a historical account of the war intrigues him. This is an instance of situational irony, where the very thing that estranges Krebs from his family and town—the war he fought in—is also what he is drawn to and interested in from his place of solitude, the porch.
Krebs, feeling isolated and lost back in his hometown, is drawn to maps and historical books because they ground him. Not only do they describe a time when he felt like a "good soldier" making a "difference ," but they describe precisely where he was in time and place, the exact opposite of his current, aimless existence.
This moment of irony ends with an ambiguity typical of ironic situations: when Krebs says "that made a difference," he could be referring to the fact that he was a good soldier who made a difference in the world or that he was a good soldier, which marks him as different from the bad soldiers. Regardless, the ambiguity of the text is ironic in a meta-analytical sense, raising questions about the accuracy of books more generally as Krebs purports to learn history by reading rather than through experience.