Mesoamerican ballgame many Caribbean islands including Cuba, Puerto Rico, and the West Indies, has been proposed as a descendent of the Mesoamerican ballgame, perhaps through the Maya. Mesoamerican ballgame The Mesoamerican ballgame was a sport with ritual associations played since 1400 BC by the pre-Columbian people of Ancient Mesoamerica. The sport had different versions in different places during the millennia, and a newer more modern version of the game, "ulama", is still played in a few places by the indigenous population. The rules of the game are not known, but judging from its descendant, ulama, they were probably similar to racquetball, where
Adoption of the Gregorian calendar is only occasionally used today. North Korea from 1997 officially counts years based on the Juche era, the first year of which is 1912. The Republic of China (ROC) formally adopted the Gregorian calendar at its founding on , but China soon descended into a period of warlordism with different warlords using different calendars. With the unification of China under the Kuomintang in October 1928, the Nationalist government decreed that effective the Gregorian calendar would be used. China retained the Chinese traditions of numbering the months and a modified Era System, backdating the first year of the ROC to 1912;