Mixed curling the house. In the 2015-16 season, a new rule called "power play" was added, which each team can exercise in one end per game, only when they have the hammer. Instead of positioning the rock in the house on the center line, it is placed to a position straddling the edge of the eight-foot circle, with the back edge of the stone touching the tee line. The opponent's guard stone is placed in line with the stone in the house and the hack. The power play cannot be used in an extra end. Mixed curling Mixed curling, also known as
Curling curlers often used 'irons' rather than stones until the early 1900s; Canada is the only country known to have done so, while others experimented with wood or ice-filled tins. Outdoor curling was very popular in Scotland between the 16th and 19th centuries because the climate provided good ice conditions every winter. Scotland is home to the international governing body for curling, the World Curling Federation in Perth, which originated as a committee of the Royal Caledonian Curling Club, the mother club of curling. Today, the sport is most firmly established in Canada, having been taken there by Scottish emigrants. The