Topless children brave the wintry weather in a military-style training session in Nanjing, East China's Jiangsu province, Feb 1, 2016. [Photo by Sun Lingke, Shi Yongxiang and Tang Shihua/Asianewsphoto]

The training session in Nanjing also touched a nerve in China. Some people linked it to news reports that Japanese children, dressed in summer tops and shorts, defy cold weather effortlessly both on daily trips to school and for winter sports. They went on to argue on Weibo that, by following the Japanese, Chinese students can learn to be stronger, both mentally and physically.

Opponents of such techniques express concerns about children's health. Winter is cold season, with many children coming down with influenza. Instead of being exposed to the cold, they argue, children should keep themselves warm.