Lindsey asked via Twitter about the free guard zone.
That rock essentially is guarding an area of the house behind it. A team with the hammer, or last rock, advantage might place a stone away from the center line (such as the red rock in the diagram) to keep the pathway to the four-foot open. The opposition might place a rock near the center line (yellow rock in the diagram) to block the pathway to the four-foot and the button.
That strategy is relatively new in curling.
Once curling equipment and indoor ice sheets became more uniform, games often became a series of “hit,” or “take out” shots. (Team 1 places a rock in the house. Team 2 knocks it out and leaves a rock in the house. Team 1 knocks that rock out and leaves one, Team 2 knocks that rock out, etc., etc., until the team with the hammer, or last rock, would score 1 point.)
As you can imagine, games could fly by, spectators might tune out until the final shots of the game, and players were aiming to score 1 point unless their opponent missed a shot. Not too exciting.
So about 20 years ago the World Curling Federation introduced the Free Guard Zone Rule (or Moncton Rule, since it was first tested in competition in Moncton, New Brunswick).
The free guard zone – the area in the field of play between the hog line and tee line but outside the house (designated in the diagram, at right) – applies to the first four stones of each end. Players are allowed to bump, but not remove, their opponents’ first two stones.
The free guard zone has increased the complexity of strategy from start to finish in games and demands players’ accuracy.
What happens if you take out one of your opponent’s first two stones?
If you knock one of your opponent’s first two stones out of play before the fifth stone of the end is delivered, that stone is placed back in its original spot. And the shooter’s stone is removed from play as a sort of penalty for the shot.