Mahjong is nearly ubiquitous in China. The clicking of tiles is a subtle background noise that visitors might notice as they stroll the streets and parks of the country. Mahjong is not new to the world outside of China, but its rising popularity is making the game into a de-facto form of Chinese cultural diplomacy. [...] Foreign visitors took note of the game's popularity and entrepreneurs exported the game from China to the US in the 1920s.