Curling is a sport of precision and strategy that pits two teams of four players against each other on an icy track. The principle is apparently simple: each team takes it in turns to throw granite stones towards a circular target on the ice, called the “house”. The aim is to place the stones as close as possible to the center of the house (the button), while trying to dislodge the opposing stones. A game is divided into successive rounds (called ends). At the end of each end, the score is determined: only the team whose stone is closest to the center scores points, at the rate of one point for each stone better placed than the closest stone of the opposing team. Both teams have eight stones each per end (each player throws two stones). In total, an official curling match is usually played over 8 or 10 ends, and the team with the most points wins.

Curling is played on a rectangular ice rink 45.72 m long and 4.75 m wide. At each end is the target (the house), drawn by three concentric circles 3.66 m, 2.44 m and 1.22 m in diameter. Players launch their stones from a starting block (the hack) and must release the stone before a line called the hog line. Each curling stone weighs around 20 kg and has a coloured handle on top to rotate it during delivery. Players are equipped with brooms (or brushes) to sweep the ice, and wear special shoes: one foot has an ultra-slippery sole (the slider) to allow fluid movement during the throw, while the other shoe has a non-slip sole (the gripper) to walk and sweep without slipping. This simple yet effective equipment enables curlers to control the speed and direction of the stones while moving with complete stability on the ice.

In curling, the two teams throw their stones alternately in each end. The skip stands on the side of the target and indicates the strategy and the target area by pointing with his broom, while one of his teammates prepares to throw from the other end. When the stone is released, one or two players from the team accompany its path, vigorously sweeping the ice in front of the stone. Why sweep? Sweeping slightly warms the ice and reduces friction, causing the stone to slide further and straighter than it would without sweeping. Players therefore adjust the intensity of the sweep to influence the trajectory: by sweeping hard, they extend the stone’s travel and soften its curve (the curl), while by not sweeping, the stone slows down faster and “curls” more (i.e. it turns and follows a curved trajectory).

An end is reached once all 16 stones (8 from each team) have been played. The points are then counted and recorded, and a new end begins in the other direction of play (the stones are thrown to the other house). During play, certain rules ensure fairness: for example, a stone must go beyond the hog line to be valid (otherwise it is removed from play), and if a player unintentionally touches a stone in play with his broom or body (said to have burnt the stone), it is immediately set aside.