From We’re History by Sarah Katherine Mergel:
In April 1971, table tennis teams from around the globe traveled to Nagoya, Japan, for the World Table Tennis Championships. Amid the games and other events, American player Glenn Cowan somehow found himself boarding the Chinese team’s shuttle bus. Since then, the two sides cannot agree on whether it happened by accident or by invitation. Nevertheless, Chinese player Zhuang Zedong approached Cowan, and they exchanged pleasantries through an interpreter. Cowan left the bus with a silk-screened print of the Huangshan mountains. The next day, Cowan sent Zhuang a t-shirt inscribed with “Let It Be,” a reference to the Beatles song of the same name. Following their exchange, the government of the People’s Republic of China (the PRC) invited the American table tennis team to visit China after the tournament ended. The American team promptly accepted. When it arrived in China on April 10, 1971, the team became the first group of Americans to visit China since the early 1950s. For ten days the Americans players, as well as the American journalists who joined them, traveled the country—visiting the Great Wall and the Summer Palace, playing exhibition games, and experiencing life in a communist country first hand.
Since the communists came to power in China in 1949, the US government had refused to recognize their government as the legitimate government of the country. Instead, Americans treated the government of Nationalist China, on Taiwan, as the rightful government of China. In the midst of the Cold War, which pitted the capitalist and communist worlds against one another in a battle for supremacy, Americans continually avoided normalizing diplomatic relations with the PRC. Furthermore, Nationalist China represented China in the United Nations. An effective “China Lobby” kept pressure on American politicians to support the non-communists in Taiwan over the communists in China. Few observers expected any shifts in the Sino-American relationship, so the Chinese invitation and the American acceptance took the world by surprise. Commentators quickly began to speak of the positive effects of “ping-pong diplomacy.”