TOKYO—Japan’s reputation for flawless manufacturing quality and efficiency transformed the country’s postwar economy, changed business practices world-wide and spawned a library’s worth of management manuals and business advice books. Now, the model is cracking.
Kobe Steel Ltd., Mitsubishi Materials Corp. and Subaru Corp. have all admitted in recent months to manipulating quality inspections, though all say no safety problems emerged. Takata Corp. declared bankruptcy last year after admitting to supplying more than 50 million...