Hersey ends his exploration of the six survivors with the details on Mr. Tanimoto's life since the bombing. As we move toward the end, Hersey sticks with his largely journalistic style in reporting the humdrum details of Mr. Tanimoto's life—you know, his car, his house, how many TVs he has… that kind of stuff.
In the last lines, though, something kind of different happens, and we get tiny moment of editorializing that has a huge impact:
He got up at six every morning and took an hour's walk with his small woolly dog, Chiko. He was slowing down a bit. His memory, like the world's, was getting spotty. (5.196).
Okay, so, straightforward enough—Mr. Tanimoto was getting old, so his memory wasn't so great, yadda yadda—but wait, what's with this larger statement about the world's memory being a bit dodgy?
Hersey doesn't editorialize a lot, so the impact of this little dip into a critique of the world's memory—which really means history, right?—is massive. In this way, Hersey ends the story with a friendly (?) poke to reader, subtly suggesting that stories like the ones he's been telling should be held close and remembered rather than falling victim to the world's own amnesia.