The two presidents first met in 2017, a year marked by an exchange of state visits that set the tone for their interactions. In April that year, Xi and his wife, Peng Liyuan, visited Trump's Mar-a-Lago estate in the U.S. state of Florida, where the two presidents dined together and Xi met Trump's family, including his grandchildren.

Chinese President Xi Jinping, his wife Peng Liyuan, U.S. President Donald Trump and First Lady Melania Trump listen as Trump's grandchildren sing a Chinese folk song and recite classics of Chinese literature in the Mar-a-Lago resort in Florida, the United States, April 6, 2017. (Xinhua/Lan Hongguang)

　　It was during that visit that Xi delivered a line often recalled in discussions of bilateral ties: "There are a thousand reasons to make the China-U.S. relationship a success, but not a single reason to break it."

　　Several months later, in November, Trump traveled to Beijing, where Xi hosted him during a series of special events. The two leaders and their spouses toured the Forbidden City along its central axis, visiting the Hall of Supreme Harmony, the Hall of Central Harmony and the Hall of Preserving Harmony -- an experience imbued with the Chinese cultural ideal of "harmony" reflected in the names of the three grand halls.

　　Walking inside the ancient royal palace, Xi told Trump that China's history can be traced back more than 5,000 years, or even earlier, and its culture has been passed down in an unbroken continuum.

　　During a chat over tea on that trip, Trump showed Xi a video of his granddaughter, Arabella Kushner, singing and reciting classical poems in Mandarin. Xi said her performance deserved an A-plus. The clip quickly resonated with Chinese netizens and went viral online.