Commentary In the past half-century, China-U.S. diplomatic relations shifted from ping-pong to a more aggressive form of contact sport. Fifty years ago, on April 10, 1971, the U.S. table tennis team became the first group of Americans to set foot in China for a friendly match. This move led to the visit of then-President Richard Nixon to China in February 1972, and also made “ping-pong diplomacy” a new term in international diplomatic relations. An event was held to mark the 50th anniversary of the ping-pong diplomacy on April 10 at the International Table Tennis Federation Museum in Shanghai. Special guests included James Heller, U.S. Consul General in Shanghai, and former Chinese ping-pong players Zhang Xielin and Zheng Minzhi. But the event didn’t receive a lot of attention from the United States and the U.S. Embassy did not send an ambassador. It seems the United States and China now have diplomatic relations …