The city of Aizu-Wakamatsu, Japan, has discovered that domestic industry can no longer sustain local employment.Credit...Ko Sasaki for The New York Times AIZU-WAKAMATSU, Japan — Mayor Shohei Muroi knows it is a tough sell to get new companies to invest in this struggling industrial city just 60 miles from Japan’s most notorious nuclear plant. So in September, Mr. Muroi did the unthinkable. He flew