New Delhi, July 23 -- Under the glare of floodlights in Shenzhen, 32 humanoid robots stepped into an octagonal ring, one after another. They threw punches, spun into kicks, fell, got back on their feet and fought on as thousands cheered from the stands. The Ultimate Robot Knockout Legend (URKL), a humanoid fighting league held last week, looked less like a technology demonstration and more like a sporting spectacle.

More than 200 teams from at least 10 countries had entered the competition. Universities, including Stanford, UC Berkeley, Tsinghua and Zhejiang, sent teams to test the intelligence that enabled the robots to see, balance, react and make split-second decisions.

This was a public demonstration of a new technological race. Aro...