As Team GB's men and women play for a place in the curling finals at the Sochi Winter Olympics, we look at how the game is played.
Curling is played by two teams of four players each. Each member of the team has their own title - a lead, a second, a vice skip and a skip.
The ice on which a curling competition is played is known as a sheet, with a 'hog line' from side line to side line running underneath the ice.
Each game is divided into eight or ten 'ends', with points added up at the conclusion of each.
The teams take alternate throws towards a circular target, known as 'the house'. The goal is to have more stones closer to the centre than the opposing team once all sixteen stones are thrown.
Two stones are thrown by each member in order. The last two, which are the most important, are thrown by the skip.
The final shot - known as the hammer - can have a strong bearing on the outcome of a match since it can knock other stones out of the way.
The skip - the most experienced player - takes responsibility for strategy. A stone is thrown by a player sliding forward whilst kneeling on one knee, releasing the stone before crossing the hog line.
Some stones will be directly aimed towards the house, whilst others might be aimed to knock the opposing teams stone out of the way.
The teams are not allowed to touch the stone once moving, but can sweep the ice ahead of it to make it move smoothly. Greater sweeping speed limits the stone from turning and lets it travel further.