2018 Winter Olympics: Understanding curling

This winter sport dates back 500 years

Photo: Benson Kua
Photo: Benson Kua

Curling is a sport in which athletes slide polished stones on ice toward a bullseye, called a house, and the stones resting closest to the center of the target score the highest points.

The earliest written reference to curling was published in Scotland in February 1541. Early versions of the game had players sliding flat river stones that had been polished by the flowing water. Due to the natural erosion, stones would vary wildly in smoothness, size and shape. The inconsistencies in the natural stones made the game more dependent on luck based than skill.

Curling was included in the first Winter Olympic Games in 1924, but did not become an official sport until the 1998 Games. 

Curling returns to the 2018 Winter Olympics in PyeongChang, with the event taking place at Gangneung Curling Centre. This is the first games to include mixed doubles curling, in which men and women play together using modified rules. 

Curling -- Tournament

Men's dates: Feb. 14-24
Women's dates: Feb. 14-25

Here's how it works:

The curling sheet is a sheet of ice, 150 feet long and 16 feet 5 inches wide with houses on each end. The smallest ring is called the tee and it has a diameter of 1 foot. It is followed by a 4-foot ring, an 8-foot ring and a 12-foot ring. The players push off on two rubber-lined hacks that sit 6 feet from the rear edges of the sheet.  

Players move their stones with a handle attached to the stone and must release the stone before the front edge touches the hog line. The hog line is 33 feet from the player's respective sides' hacks and is 93 feet from the other side's tee. If the player releases a stone after the hog line, the stone is taken out of play.

Stones that rest between the hog line and the tee line, but not those within the rings of the house, are in the free guard zone. Players are allowed to bump stones in this area, but they aren't allowed to remove a stone from play.

Once a stone is in play, another player from that team can sweep the ice in front of the stone with a curling broom as the stone slides. This lowers friction and increases the distance that the stone will slide. Only stones that are currently sliding, including stones that have been bumped by the stone the player slid, can have the ice around them swept.

Each shot is rated on a scale of 1-4, with 4 being the highest score a shot can receive. In some contexts, bonus points can be added. It's not unheard of for a player to score a 5 or a 6 on a 4-point shot.

A percentage is calculated by quadrupling the total throws and dividing that number by the number of points awarded. The winner is the player who has the highest percentage calculated.

Curling -- Mixed doubles

Dates: Feb. 8-13

Here's how it works:

Mixed doubles starts with two stones, one from each team, already placed on the sheet. These starting stones are eligible to be counted in the final score. Teams are composed of one woman and one man.

Each team throws five stones per game, with the player throwing the first stone on a team also throwing the final stone and the other team member throwing the other three stones. The player who isn't throwing may also sweep for the other player's stone.

The scoring is calculated in the same way as for regular curling.