In 1839, the first baseball game in history was held in Guppstown, New York, USA. In 1860, professional baseball players began to appear in the United States. In 1871, the United States established the “National Professional Baseball Players Organization”; in 1876 the organization was renamed “American Baseball Federation.” In 1881, another national professional baseball organization was established, which was later the “National Professional Baseball Federation.” In 1884, the first competition between the two organizations was held, the “World Baseball Championship”. Since then, in 1910, US President William Howard Taft officially approved baseball as the “national ball” of the United States. The baseball caps were also popularized in various baseball teams. At the beginning, the players only wanted to block the sun. Later, regardless of the weather, people would bring baseball caps in the game. In 1873, baseball was introduced to Japan from the United States. The Japanese professional baseball team was founded in 1934. The baseball cap was also introduced to the Japanese baseball team. After the Second World War, baseball was quickly launched in European countries. Now baseball is being played in more than 100 countries and regions on five continents. Baseball caps are popular in the world, but they are also limited to baseball players. People don’t use baseball caps as a life item. Baseball caps have become the iconic decoration of baseball players.