University students took part in the Mynabi Job Expo, a job fair hosted by Minichi Communications in Tokyo in January.Credit...Tomohiro Ohsumi/Bloomberg News TOKYO � Kenichi Horie was a promising auto engineer, exactly the sort of youthful talent Japan needs to maintain its edge over hungry Korean and Chinese rivals. As a worker in his early 30s at a major carmaker, Mr. Horie won praise for his de