Curling

Worcester Cup Bonspiel 2014
The Basics

Curling is a sport where two rinks (teams) of four players each throw stones down a sheet of ice.  The teams alternate throwing rocks with each curler throwing two stones. After both teams finish throwing their rocks, the end is completed and points are determined if at least one team finishes with a stone touching the house (the large ring on the ice). The team that gets closest to the button (the center of the house) scores as many points as stones they have closer than the opposing team’s closest stone to the button. Whichever team scores a point throws the first stone during the next end.

After a predetermined amount of ends (usually 8 at most club level competitions), the team with the most points wins.

Rinks 

Each curling rink is composed of four curlers.  Each curler throws two of their team’s stones each end. During a game, the order that stones are thrown cannot be changed. One curlers throws their rink’s first two stones, another curler throws the next two stones, another curler throws the next two stones, and the last member of the rink throws the final two stones. The three people not delivering the stone are positioned with two sweeping each stone and another person inside the house helping to decide the shot and/or helping relay information about the course of the rock as it heads down the ice and whether or not sweeping may be needed.

Commonly, the player throwing first stones sweeps for the other three curlers, the player throwing second sweeps for the first two stones and the final four stones, the player throwing third sweeps for the first four stones and then goes to the house for the last two stones, and the player throwing last calls shots in the house for the first three players (six stones) and then delivers the final two rocks for their team each end.

Winning an End (even while Losing an End)

Beyond the basics, each rink wants to accumulate enough points to win the game. In curling, the team that has the hammer (throws the last stone of an end) has an advantage, but this advantage goes away once they score points as the hammer goes to the team that lost an end. Because of this, the goal of the team with the last stone (or hammer) is to score as many points as possible before giving the advantage to the other rink. On the other side, the rink without the hammer wants to give up the fewest points possible (or steal points). This means that in an evenly matched game, the team without the hammer could give a single point in an end and be happy to get the hammer advantage while the team who scored the one point may be disappointed that they did not do more with that advantage.

Free Guard Zone Rule

One problem that curling faced is that the team with a lead could simply knock out the rocks of their opponents to preserve a lead. If a team was up 2-0 and was skilled at throwing takeouts (hard shots designed to knock an opponent’s rocks out of play), they could simply throw away their first stone and then take out seven of their opponent’s eight stones with their remaining seven rocks, give up a point, and get back the last stone advantage. The team with any lead, however small, held a distinct advantage.

To help alleviate this problem, the free guard zone rule was created. The free guard zone rule forbids a rink from removing any of their opponent’s rocks that are in play but outside the house (the ringed zone where points are scored) with their first two stones. This means that the first two stones each team throws are temporarily protected if they are positioned outside the house, guarding future shots.

Simple Strategy

Because the first shots are protected when used as guards, both rinks often use these stones as guards in a way to help their team have a successful end.

The team throwing first rocks often wants to try to limit their opponent to one point or steal a point themselves. To do this, the strategy used is often to throw their first two stones near the middle in hopes of getting a subsequent stone behind that wall. If the team gets a stone behind the wall and counting (closest to the center of the house), often they will continue throwing more guards up in hopes of holding on to get their one point.

The team with the hammer wants two things. First, they want a chance to score multiple points. Second, they want an opportunity to get a point should everything go wrong. While the team throwing first wants to clog up the middle, the team throwing second wants to put guards up on the side in hopes of getting one stone behind cover on the side of the house. Keeping stones in the house as far apart as possible, while still counting, lessens the risk of an opponent being able to take out multiple stones with one rock and thus increases the chance to score multiple points.