World War I began in August 1914 and on the Western Front quickly bogged down into trench warfare. In Belgium and northern France, British and French troops were dug into trenches facing German troops a few hundred yards away. The troops continued firing back and forth until a remarkable event occurred, which historians have labeled "The Christmas Truce." On Christmas Eve, along several sectors of the front, British and German troops stopped firing and eventually came out into the area between the trenches to sing Christmas carols and exchange small gifts. The truce lasted until Christmas night in most areas of the front, although it continued until New Year's Day in a few areas. Most of the troops' commanding officers were unhappy with the truce-they would have preferred the troops to keep fighting through Christmas-and in the future they often used a policy of rotating troops around the front so that the same British and German troops did not face each other for more than relatively brief periods. Can game theory explain why the Christmas Truce occurred? Can game theory help explain why the commanding officers' strategy was successful in reducing future unauthorized truces?