The Curling Manual
Table of Contents
Section 1 Overview of the Sport
Curling is a team sport played on ice. The Olympic medal sport, probably originated in the 1500's on the lakes and ponds of Northern Europe. Two teams of four players each slide 42-pound granite rocks down a sheet of ice 120 feet long by 15 feet wide (see Figure 1.1). The rocks are delivered from one end of the sheet to the other toward the center of a 12-foot diameter target.
Curling is played actively in
more than thirty countries in Europe, Asia, North America,
Curling can be enjoyed by nearly all age groups for social play as well as high-level competition such as the Olympic Games. Curling awareness has increased dramatically since the Games in Torino, Italy in 2006 where media coverage of the sport dramatically increased in the United States and Canada. With the 2018 games complete, many teams are preparing for competition in the Winter Games in 2022.
The object of the game is to score more points (rocks) than your opponent. In each “end”, like an inning in baseball, teams throw eight rocks each (two per player, alternating with your opponent) toward the twelve foot diameter target called the “house”. All rocks closest to the center count as one point as long the opponent does not have one closer. The targets are usually painted into the ice just below the surface at both ends of the sheet of ice, to allow the game to be played back and forth, usually eight or ten times. Eight end games take about two hours. Each player throws two rocks toward the target, alternating with the opponent. Rocks traveling down the ice will “curl” anywhere from six inches to six feet. After all sixteen rocks have been thrown the score is determined. Teams score one point for each rock closest to the center of the house without an opponent’s rock closer. In each end, only one team can score. As the rocks are thrown, they are intentionally rotated clockwise or counter-clockwise (depending on the shot). This rotation causes the rocks to curve (curl) as mentioned above.
A unique part of curling is the concept of sweeping. Players vigorously sweep, or brush the ice in front of the rock. The friction of the brooms momentarily melts a molecular layer of the ice in front of the rock. This thin layer lubricates the bottom of the rock allowing it to travel farther and straighter. In recent years, the sweeping motion has been known to scratch the ice slightly helping to steer the rock. Good sweepers can manipulate the distance and curl resulting in rock placement.
Traditional Four on Four
Most games are played four against four, each player throwing two rocks per end. The number of ends varies depending on the level of play, generally eight ends or ten. In the four-against-four format there are many different categories based on gender and age.
A format that debuted at the 2018 Olympics is mixed doubles. The object of the game is the same but it is played two against two. One male, one female. Only five rocks are thrown by each team in each end. One payer throws the first and last rocks while the other throws the middle three. The order can switch every end if so desired. Two rocks are “prepositioned” before play begins, one in the house and one in the free guard zone. Refer to the WCF rules for more detail.
The objective of wheelchair curling is the same. There are some basic rules that the curlers play by such as, no sweeping, the chairs must contact the ice surface, and you can deliver by hand or by throwing device. Wheelchair curling is also mixed gender. Also refer to the WCF website for more detail.
The Playing Area
As mentioned earlier, the game
originated on the frozen lochs of
Ice that is formed by cold air
is known as "natural" ice.
For natural ice to occur, obviously the temperature must be below 0 C
(32 F). This limited the growth of curling to the
more southern latitudes. When the
sport finally came to North America (early 1800's), it was primarily played
In the early 1900's, refrigeration technology allowed ice to be prepared in regions where winter temperatures are often above 32. This ice is known as "artificial" ice. Almost all curling facilities now have artificial ice, which allows curling to thrive in all latitudes.
Artificial ice is produced using a process of compressing ammonia or Freon and then allowing it to expand and cool. This cooling process removes heat from the playing surface, lowering the temperature, and creating ice. This is done by running cooling pipes under the playing surface. The pipes are usually four inches apart, run the length of each sheet, and carry cold liquid chilled by the ammonia or Freon. A four-sheet club has approximately six miles of pipe under the ice.
Curling is slow to arrive in the middle latitudes. To date, dedicated curling facilities in warm climates (35 degrees North latitude and below) are few and far between. The refrigeration equipment and compressor is driven by one or more large capacity electric motors. These motors draw an enormous amount of electricity making it very expensive to make ice. Curling in these climates usually happens at ice rinks that share ice time with skaters, hockey players and curlers.
The Sheet of Ice
The modern sheet of ice is approximately fifteen feet wide by about 140 feet long. Rubber “hacks” are placed in the ice for foot traction during for delivering the rocks. The dimensions of a sheet are subject to change from time to time.
Figure 1.1 Approximate Sheet Dimensions – See the WCF website for the most current dimensions.
The hog line has two functions. The far hog line serves as the leading edge of the area “in play” meaning rocks must fully cross the hog line to stay in play during the end. The nearer hog line serves as the farthest edge of the delivery area, meaning all rocks must be released before they touch the near hog line. It’s an odd name for a boundary line.
The name hog line comes from an old Scottish shepherding term. Baby sheep are known as “hogs”. The line of slow-moving baby sheep (not pigs) at the trailing edge of the pack was referred to as the hog line. This line of sheep was the farthest back a sheep could be and still be part of the group. You can draw the distant similarity. In curling, it’s the farthest point a rock can be from the center and still be in play.
Originally, the hog line was used only to determine rocks in play. It was not used as a release boundary since most deliveries were essentially from the hack. As players began using the slide in delivery (1940s and 50s) rules were put in place to prevent a player from sliding the entire length and placing the rock in house. The near hog line seemed to be a suitable spot. Starting in the 1950s, the body was not allowed to cross the hog line during the delivery. In 1973, the international organization modified the rule stating the stone must be released before it touches the hog line and the body would be allowed to slide past it. Today, the rock is removed from play if it touches the hog line prior to release and in some cases is measured by high tech sensors in the handles.
From a distance, curling ice appears perfectly smooth. After a closer look, you'll notice that the ice appears bumpy. The rocks ride on these small frozen bumps called "pebble". The pebble is put on before each game with a machine that works like a flower sprinkler. Without the pebble, there would be too much friction between the ice and the rocks, making it too difficult to throw the rocks the full distance. Pebble is what makes curling a “finesse game”.
The ice is maintained between games by sweeping off debris and re-pebbling. The build-up of pebble is generally scraped off the surface two or three times a week, or as much as possible. A special scraping machine is manufactured just for curling ice. The resurfacing machine removes the build-up of pebble and any frost that has settled before new pebble is applied.
Occasionally, due to the uneven freezing of the surface, the entire area is flooded and allowed to freeze slowly. This levels the ice and is done about every six weeks.
It is very difficult to prepare a perfectly level ice surface. Even though most imperfections can't be seen, the way the rocks behave while in motion may indicate the presence of ridges and troughs. This is part of the game. Skips must determine what the sheets are like as early as possible, similar to "reading" the green in golf.
The ice surface temperature is maintained somewhere in the 22-25 degree range. In some cases, sophisticated equipment is used to measure and maintain these temperatures.
Up until the mid-1980’s, the ice surface was relatively crude. Ice was made with mineral-laden tap water. Pebble was added every game and built up over time. Corn brooms littered the ice with corn chaff and debris. The ice was relatively slow and straight and games were played with mostly takeouts. A “draw” game was played by seniors.
Two major contributions or breakthroughs in the 1980’s changed the game.
Purified ice and regular scraping completely changed the ice surface and therefore change the game. The ice was faster with more curl. Teams immediately took advantage by shifting from a takeout game to a draw game and the new era of curling began.
The air temperature in most clubs is controlled. The ideal air temperature at chest level is around 40 F. Not only is it comfortable for the curlers, the heat keeps the relative humidity lower so frost won't build up on the ice. Some clubs have dehumidification systems. This further decreases the relative humidity. Lower latitude clubs with no heating capabilities usually have frost problems. Higher latitude clubs with no heat are very cold and dry. In extremely cold and dry cases, the ice will ”sublimate”. Sublimation is the process of ice changing to vapor without passing through the liquid stage.
Teams are made up of four players. Each player throws two rocks, alternating with the opponent. The first position is known as the Lead and throws the first two rocks. The second position is known as the Second and throws the second two. The third position is known as the Vice Skip and throws the third two rocks. The fourth position is known as the Skip (calls each shot and is the team captain) and in most cases throws the last two rocks.
The skip controls the game by determining the game strategy and calling all of the shots. Since the rocks curl as they travel down the ice, the throwers must aim at a point other than the intended resting point. The skip is responsible for providing an aiming point. He or she places the broom upright, directly over the desired aiming point. The skip is also responsible for determining whether sweeping is necessary and communicating this to the sweepers*
The use of a team coach is becoming more popular. Curling coaches are required to “passively coach” the team. Rules state that the coach cannot interact with the team during play. Even with the existence of a team coach, the skip must call all of the shots. Coaches generally communicate before, after and in some cases, during a break half way through the game. Time-outs are another opportunity for coaches to intervene.
* On more skilled teams the skip is not responsible for determining sweeping. The sweepers judge the distance and sweep when necessary (See the Sweeping section).
Essentially, there are only two types of curling shots, the draw and the takeout. There are many variations of these two shots, however.
Draws are shots that are only thrown hard enough only to reach the field of play at the other end. Takeouts are designed to remove rocks from play.
As mentioned earlier, we intentionally rotate the rocks as we throw them. These rotations are called turns. A clockwise rotation (for a right handed person) is called an In-turn while a counter-clockwise rotation is called an Out-turn. The names originally come from the direction your elbow took as you were throwing. (the elbow pointed out as you rotated the out-turn and vice versa). This is no longer appropriate because the elbow shouldn't move in a proper delivery. The names remain.
Below is a list of possible draw shots:
Below is a list of possible takeout shots:
All shots called by the skip have an associated hand or arm signal. Hand signals were developed due to the length of the sheet of ice (the option is to scream to other players at the other end). Also, many curling clubs are so loud that talking is difficult.
Skip's signal can vary dramatically. Listed below are the most common signals used. There are two basic types:
1. Signals to determine the shot
Tapping the ice with the broom (intended resting point)
Right arm extended (in turn for right-handers)
Left arm extended (out turn for right-handers)
Tapping the rock with the broom (intended takeout target)
2. Signals to determine the weight
· Tapping the hack with broom (intended weight)
· Touching the arm at the wrist, elbow or shoulder
· Touching the upper body at the waist, chest and neck
Figure 1-3. The skip then holds the broom where she wants you to aim and extends her arm to indicate the turn (rotation). We know from Figure 1 that she wants the stone in the four-foot so she estimates how much the stone will curl and places the broom at the aiming point. For this shot, she calls for an out-turn (counterclockwise) by extending her left arm.
Games consist of either eight or ten "ends" depending on the level of competition. League and bonspiel games are generally eight ends while championship games are ten ends. An end in curling is similar to an inning in baseball. Each end takes approximately fifteen minutes, so an eight end game would generally take two hours to play.
Each game, the teams are assigned a sheet of ice (similar to a lane in bowling) at the curling club. Curling clubs have anywhere from two sheets to eight sheets of ice.
The game begins with a handshake. It is customary for each player to shake hands with each opposing player and each teammate. Shake hands with your opponent first.
In league games, it is customary to NOT practice before a game. Most curlers take a few “practice slides" before throwing the first rock. This is done by sliding out of the hack with no rock. Do not throw rocks prior to any game unless it is specifically mentioned in the league or competition rules. Practice slides help limber-up the body (pre-game stretching is also recommended, see the Delivery Section) prior to throwing the first rock.
In championship games, a short pre-game practice is allowed, generally six to ten minutes per team.
The Coin Toss
The vice skips on each team toss a coin to determine who has the last rock advantage in the first end. In most cases the winner of the coin toss chooses to throw the last rock, the loser of the toss chooses the rock color.
In championship games the hammer is not determined by chance. It is determined by the Last Shot Draw (draw to see who has last rock). This is done before each game. The winner of the draw contest chooses hammer or last practice.
At this point, the skips move to the opposite end of the ice and the team not delivering moves between the hog lines. The skip calls the shot, the first rock is thrown, and the game is on.
Note: In many clubs, the rocks are numbered from one to eight. Unless told otherwise, the lead should throw rocks number one and two, the second throws three and four and so on.
Each player will throw two stones per end, alternating with the opponent. Your team throws one; the opposing team throws one, and so on. As the lead is throwing, the second and vice are designated sweepers, with the skip calling the shots. When the second is throwing, the lead and vice are the sweepers. When the vice is throwing, the lead and seconds are sweeping. When it comes time for the skips to throw, the vice skip takes over responsibility of the house and calls all sweeping for direction. The lead and second remain as the sweepers for the skip's shots. Yes, the lead and second sweep more than the vice, and the skip doesn't sweep at all.
Understanding where to position yourself on the ice is critical to team performance as well as playing by the rules. The leads and seconds must position themselves between the hog lines unless they are about to sweep or about to deliver a rock.
If you are about to deliver a rock, position yourself behind the hack and remain quiet and still as your opponent delivers. As soon as the opponent delivers the rock, choose your rock and move into the hack area. While the opponent's rock is still in motion, begin the setup process in the hack (described in the Delivery section).
If you are about to sweep, position yourself on the tee line approximately two feet from the sideline. Confirm the shot and weight with the thrower. As your teammate begins to deliver, start moving forward and to the center trying to "meet" the rock near the hog line. At this point you may begin sweeping the rock if necessary.
When you have stopped sweeping, return to the other end of the ice. Be sure not to walk down the center of the sheet, preventing the opponent from viewing. As you are walking back, try not to distract the opponent in the hack. If time permits, stop and remain still while the opponent is delivering.
Completing the End
Once all sixteen rocks have come to rest, the vice skips from each team agree on how many rocks are counting and to which team they belong. Only one team can score in an end and the most any team can score is eight. Occasionally, when the counting rock or rocks can't be determined by eye, a special measuring device is used (see the Measuring Rocks section). Normal scoring in an end may be one, two, three or even four rocks. Scores of five, six and seven are less common. Scoring all eight rocks is as rare as a hole-in-one in golf and many players never see one.
Having last rock in any end is clearly an advantage. It’s called having the “hammer”. The hammer in the first end is determined before the game by a coin toss, generally by the vice skips. In championship play, the hammer is determined by a draw contest just before the game. Teams choose the best draw player and the closest to the button has choice of hammer OR rocks.
After each end, when all sixteen rocks have come to rest, one team will score one point for every rock it has closest to the center. Only one team can score in an end. The scoring team gives up the hammer in the next end. If no team scores in an end, either deliberately or by accident, the hammer is retained.
The vice skip of the scoring team is responsible for posting the score after each end. On the curling scoreboard, numbers 1 through 16 (possibly 17, 18, 19 etc.) are painted horizontally from left to right. These numbers represent the rocks scored. At one end of the scoreboard, there is a stack of individual numbers from 1 to 10. These represent the ends and are hung either over or under the painted numbers. Since teams throw different colored rocks, the ends are hung above or below the painted numbers depending on color. In curling, the rocks scored are posted cumulatively, meaning two rocks scored in the second end are added to whatever was scored in the first end (if any).
The team scoring in the end will give up the hammer and throw first in the next end. This means that the scoring team will never have last rock advantage after just scoring.
At the completion of the game, it is customary to again shake hands with your opponents and your teammates. It is now time for broomstacking. Most curling clubs have some sort of gathering area for broomstacking teams. There will usually be table set up behind each sheet of ice designated for this.
Curling is one of only a few sports that allow a team to concede before the end of the game. It is customary to concede the game if you think the lead is insurmountable, even if it is mathematically possible to still win or tie. Of course, if it is mathematically impossible to tie or win, the game is over and the losing team should immediately shake hands.
Rule of Thumb
If you don’t think you can win the game, concede. It is never appropriate to keep playing just to “practice”.
Most people find that fifteen minutes per end is a comfortable pace for the game. In fact, most league schedules and game times rely on this. Slow play not only delays the following games, it allows players to get bored and/or cold. It is important to be ready to throw when it is your turn. Skips must also be aware of the time. Over-analyzing and chatting will delay the game.
Like golf, slow play is never appropriate. Fifteen minutes per end!!!
At all championship level games and in some bonspiels, time clocks are used to control the speed of the games. The reason for time clocks is to prevent one team from taking enormous amounts of time to call the game. The clock is similar to a chess clock and each team has xx minutes to complete a ten end game. Teams out of time lose the game. In the 2014-15 season, the game time was changed from total time to only “thinking time”. Thinking time does not penalize a team for throwing mostly slower, draw shots.
The clock begins when the opponent’s rock comes to rest and the skip is allowed to take control of the sheet. The clock will continue to run until the next rock is thrown.
It is necessary for the lead and second to be ready to play when the opponent's rock comes to rest. This is a noticeable difference in the pace of the game. Teams under the clock no longer have the luxury of casually moving into the hack and taking their time. The pace at the beginning of end is usually faster than the pace at the end due to the vice skips and skips discussing the shots. The faster the leads and second are, the more time the back end has to discuss the strategy.
Curling equipment comes in a range of complexity and cost. The only essential items are a "slider" and a "broom". A slider is a piece of Teflon, plastic or steel that is slipped onto one foot in order to easily slide down the sheet of ice. Today’s game of curling is designed around the ability to slide with no effort. The other foot usually has a rubber-soled shoe used to grip the ice. To throw the rock, one foot pushes while the other slides. Right-handed curlers push with their right foot and slide on their left.
Figure 1-4. Regular curlers use different types of equipment. In addition to the rocks and sliding device (supplied by the club), most curlers have their own curling shoes and broom.
The broom or brush is used to sweep the ice (polish it, actually) and most curling clubs have brooms available for use. See the Advanced Equipment section for the CurlTech choice on purchasing a broom.
More advanced curlers may choose to purchase special curling shoes with a built-in slider. See the Advanced Equipment section for the CurlTech recommendation for curling shoes.
many manufacturers of curling equipment in the
Curling facilities own a variety of equipment.
The most expensive and complex equipment in the club is the refrigeration system used to make artificial ice. Heating, dehumidification and water purification systems are also complex and expensive.
The next most
critical piece of equipment is the rocks.
They are made from solid chunks of special, high-density granite found
Most clubs have club-type brooms available for use by novices, open houses or club rentals. Slip-on sliders and sliding devices should also be available at the club.
Other equipment at the curling club includes measuring devices, ice scrapers, large maintenance brooms and scoreboards.
The Spirit of Curling
"Curling is a game of skill and traditions. A shot well executed is a delight to see and so, too, it is a fine thing to observe the time-honored traditions of curling being applied in the true spirit of the game. Curlers play to win but never to humble their opponents. A true curler would prefer to lose rather than win unfairly.
A good curler never attempts to distract an opponent or otherwise prevent him/her from playing his/her best.
No curler ever deliberately breaks a rule of the game or any of its traditions. But, if he/she should do so inadvertently and be aware of it, he/she is the first to divulge the breach.
While the main objective of the game is to determine the relative skills of the players, the spirit of the game demands good sportsmanship, kindly feeling and honorable conduct. This spirit should influence both the interpretation and application of the rules of the game and also the conduct of all participants on and off the ice."
The previous text was taken verbatim from the World Curling Federation (WFC) curling handbook. The Spirit of Curling is familiar to all who curl and its principles guide the sport.
Curling is one of the few sports in the world that emphasizes etiquette. All games, regardless of level, start and finish with handshakes. In most league play, there are no referees or judges. Adhering to the rules is based on the honor system and good shots are admired by all. Missed shots are never cheered.
Curling is a Medal sport in the Olympic winter games. This status has increased the competitive nature of the game, as well as overall interest in the sport. Despite the competitive aspect of the game, curling remains a highly social and gracious sport for all age groups.
One tradition in curling is called broomstacking. The term refers to the social get-together between opponents after each game. Originally, curlers, after completing half of a game on the pond, would stack their brooms in front of the fire and enjoy beverages with the opponent. In most cases they would resume the game, if able. This tradition is alive today, although teams now wait until after the game. It is expected that you partake in broomstacking after every game. The original pond curlers most likely enjoyed their social time with the consumption of spirits. Today’s game is very similar but people are more conscious of and knowledgeable about alcohol consumption.
There is also broomstacking at all competitive levels such as, national, and world championships. Although the focus of these competitive curling events is on determining a champion, the social etiquette is still there. Even at the most competitive levels, depending on the venue, teams will get together after the game for friendly discussion.
Broomstacking at all levels leads to the development of world-wide social networks. Lifelong relationships are developed and forged through the broomstacking concept.