TOKYO—“Recession,” “stagnation,” “slump,” were the ominous labels I constantly read describing Japan before I moved here in late 2009. After I’d settled in, a better word seemed “kaiteki,” which means “comfort,” and conveys a wide range of virtues like convenience, reliability, safety, even charm. I was struck by the disparity between the world’s perception of Japan and the remarkable feeling of prosperity here—compared not just with the bubble-era Japan I saw when last living here 20 years earlier, but with the America I experienced in the interim, during its own boom times.

Tokyo...