Several things come in groups of nine, including in politics, sports, games, and history. Nine is also an important number in some mythologies and literary works.
The Supreme Court of the United States has nine justices on it. There are nine innings in a game of baseball, and nine balls are racked in nine-ball billiards. There are nine squares on a tic-tac-toe board.In addition to the previous examples, there are nine months in an average human pregnancy. For historical examples, the enemies of Egypt were often denoted by nine bows, each for an individual threat. Dante's Divine Comedy describes nine circles of hell. During the Middle Ages, there were nine divine figures known as "Worthies" who were said to symbolize the ideals of chivalry. Some occult legends from the same period describe nine men as the ethereal keepers of science and time. In J.R.R. Tolkien's works, there are nine rings given to mankind. Until 2006, our solar system was believed to house nine planets.
Nine is an arc number for many things both historical and fictional in China, where it is considered a lucky number. For instance, many dynasties used a nine-rank system in their hierarchy. Nine is often closely related to tales of dragons and Emperors. There is a district in Hong Kong named Kowloon that literally translates to "nine dragons."