One of the defining narratives of modern China has been the migration of young workers—often girls in their late teenage years—from the countryside into sprawling cities for jobs in factories. Many found work at Foxconn, which employs nearly one million low-wage workers to hand-assemble electronic gadgets for Apple, Nintendo, Intel, Dell, Nokia, Microsoft, Samsung, and Sony.

So it was a surprise when Terry Guo, the hard-charging, 61-year-old billionaire CEO of Foxconn, said last July that the Taiwan-based manufacturing giant would add up to one million industrial robots to its assembly lines inside of three years.

The aim: to automate assembly of electronic devices just as companies in Japan, South Korea, and the United States previously automated much of the production of automobiles.

Foxconn, one of China's largest private employers, has long played an outsize role in China's labor story. It has used cheap labor to attract multinational clients but now faces international scrutiny over low pay and what some see as inhumane working conditions.