Once you start playing in USCF rated chess tournaments, you will most likely be using a clock. The games are timed, so that one person isn’t allowed to “sitzfliesch,” a German word they used to use meaning to sit there and not move until your opponent practically falls over from exhaustion! That’s what used to happen in chess tournaments before the chess clock was invented. One chess tournament lasted fourteen hours, which caused people to begin to try to come up with a solution. First they tried using hour glasses, but the differences in humidity caused problems and inconsistencies. Then they invented the “tumbler clock,” which was a great addition to the chess world, and allowed chess to become a spectator sport instead of a contest to see who could sit and stare at the board the longest.