In the years since Mao Zedong’s communist revolution in 1949, relations between the People’s Republic of China and the United States had been clouded by Cold War propaganda, trade embargos and diplomatic silence. The two superpowers had met on the battlefield during the Korean War, but no official American delegation had set foot in the People’s Republic in over 20 years.

By 1971, however, both nations were looking to open a dialogue with one another. China’s alliance with the Soviet Union had soured and produced a series of bloody border clashes, and Chairman Mao believed ties with the Americans might serve as a deterrent against the Russians. U.S. President Richard Nixon, meanwhile, had made opening China a top priority of his administration. In 1967, he had written, “We simply cannot afford to leave China forever outside the family of nations.”

The two countries eventually opened secret communications, but the real breakthrough came courtesy of a public encounter between a pair of ping-pong players. During the 1971 World Table Tennis Championships in Nagoya, Japan, 19-year-old U.S. player Glenn Cowan hopped on a shuttle bus carrying the red-shirted Chinese national team. Most of the Chinese eyed the shaggy-haired American with suspicion, but Zhuang Zedong, the team’s greatest player, stepped forward to shake Cowan’s hand and speak to him through an interpreter. He even presented the teenager with a gift: a silk-screen picture of China’s Huangshan mountains.

Cowan, a self-described hippie, returned the gesture the following day by giving Zhuang a t-shirt emblazoned with a peace symbol and the Beatles’ lyric “Let It Be.” Photographers caught the incident on film, and the unexpected good will between the U.S. and Chinese teams soon became the talk of the tournament.

Zhuang and the rest of the Chinese players had arrived at the 1971 championships with strict orders to avoid contact with the Americans, but upon learning of the gift exchange, Chairman Mao took it as a political opportunity. “Zhuang Zedong is not just a good table tennis player,” he observed, “he’s a good diplomat as well.” A few days later, as the U.S. team was preparing to leave Nagoya, Mao shocked the world by inviting them to make an all-expense paid visit to China. After checking with their embassy, the American players accepted. “I was as surprised as I was pleased,” President Nixon later wrote in his memoirs. “I had never expected that the China initiative would come to fruition in the form of a ping-pong team.”

The historic visit began on April 10, 1971, when 15 American table tennis players, team officials and spouses crossed a bridge from Hong Kong into China. The U.S. team was diverse, including everyone from the hippie Glenn Cowan to a college professor to a Guyanese immigrant to a pair of high school-age girls. None of the players were particularly accomplished at ping-pong—the U.S. men’s team was ranked 24th in the world at the time—and most had been forced to beg or borrow the money to make it to the championships in Japan. Now, only a few days later, they had inadvertently become the most important American diplomats on the planet. A cadre of Western journalists was set to follow their every move, and a few members of the team were enlisted to serve as correspondents for newspapers and magazines.

After crossing behind the “Bamboo Curtain,” the U.S. team spent 10-days traveling through Guangzhou, Beijing and Shanghai and taking in the sights and sounds of the People’s Republic. “’Everything was different from anything I’d ever seen,” player Tim Boggan later told the New York Times. “The streets were different, the food was different. The people, of course, were different. The bicycles were different.” The U.S. players were treated like visiting dignitaries and lavished with banquets and meals, but the specter of the Cold War was never far off. Statues and posters of Mao Zedong and loudspeakers blaring military music seemed to be everywhere. During one stopover, team president Graham Steenhoven noticed that a “Welcome American Team” banner had been hung over a wall painted with the words “Down With the Yankee Oppressors and Their Running Dogs!”

Along with visits to the Great Wall, the Summer Palace and a revolution-themed opera, the U.S. players also participated in a series of exhibition ping-pong matches held under the slogan “Friendship First and Competition Second.” It was clear that the world-class Chinese players had taken the theme to heart. They won the majority of the contests in a walk, but let the Americans take the occasional game in the spirit of sportsmanship. “I knew I was not only there to play,” Chinese competitor Zheng Minzhi told the New York Times, “but more important, to achieve what cannot be achieved through proper diplomatic channels.”

The American trip culminated at Beijing’s Great Hall of the People, where the team had a historic audience with Chinese Premier Zhou Enlai. The meeting was mostly a formal exercise—Zhou congratulated the players on opening “a new chapter in the relations of the American and Chinese people”—but it also had its lighter moments. Glenn Cowan, who had caused a media sensation by touring China in a floppy yellow hat and tie-dyed jeans, raised his hand at one point and asked the Premier what he thought of the American hippie movement. Zhou was momentarily left speechless. “Youth wants to seek the truth and out of this search, various forms of change are bound to come forth,” he finally replied. “When we were young it was the same, too.”

The American table tennis team would leave China on April 17, arriving back in Hong Kong to a sea of reporters and news photographers. By then, the “ping heard round the world,” as Time Magazine had called it, was already bearing diplomatic fruit. On April 14, the same day that the American players met with Zhou Enlai, President Nixon had announced that the United States was easing its travel bans and trade embargos against China. The American and Chinese governments soon opened new back-channel communications with one another. In July, U.S. National Security Advisor Henry Kissinger made a secret trip to Beijing.

The ripple effects of what had become known as “Ping-Pong Diplomacy” only continued the following year. In response to the American trip, the Chinese sent their table tennis team to the United States for an eight-city tour. Even more earth shattering was Richard Nixon’s February 1972 visit to the People’s Republic, which marked the first time in history that an American president had traveled to the Chinese mainland. As part of the eight-day trip—Nixon would call it “the week that changed the world”—the President met with Zhou Enlai and Chairman Mao and took the first steps toward normalizing U.S.-Chinese relations. Writing about the visit years later, Nixon noted that the Chinese leaders “took particular delight in reminding me that an exchange of ping-pong teams had initiated a breakthrough in our relations. They seemed to enjoy the method used to achieve the result almost as much as the result itself.” Perhaps the most fitting table tennis metaphor came courtesy of Mao himself: “The little ball,” he said, “moves the Big Ball.”