The British women's curling team competing in the final match at the 2002 Winter Olympics in Salt elipsis
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The game of curling is thought to have been invented in late medieval Scotland, with the first written reference to a contest using stones on ice coming from the records of Paisley Abbey, Renfrewshire, in February 1541. Two paintings (both dated 1565) by Pieter Bruegel the Elder depict Dutch peasants curling—Scotland and the Low Countries had strong trading and cultural links during this period, which is also evident in the history of golf.
The game of curling was already in existence in Scotland in the early sixteenth century as evidenced by a curling stone inscribed with the date 1511, uncovered along with another bearing the date 1551, when an old pond was drained at Dunblane, Scotland. Kilsyth Curling Club claims to be the first club in the world, having been formally constituted in 1716 and is still in existence today Kilsyth also claims the oldest purpose-built curling pond in the world at Colzium – in the form of a low dam creating a shallow pool some 100 x 250 metres in size, though this is now very seldom in condition for curling due to warmer winters.
The word curling first appears in print in 1620 in Perth, in the preface and the verses of a poem by Henry Adamson. The game was (and still is, in Scotland and Scottish-settled regions like southern New Zealand) also known as "the roaring game" because of the sound the stones make while traveling over the pebble (droplets of water applied to the playing surface). The word derives from the Scots language verb curr , which describes a low rumble (a cognate of the English language verb purr). The word does not take its name from the motion of the stones, although today a stone deviating from a straight-line trajectory is said to curl.
In the early history of curling, the rocks were simply flat-bottomed river stones that were sometimes notched or shaped; the thrower had little control over the rock, and relied more on luck than skill to win, unlike today's reliance on skill and strategy.
It is recorded that in Darvel, East Ayrshire the weavers relaxed by playing curling matches. The stones they used were the heavy stone weights from the weavers 'warp beams', fitted with a detachable handle for the purpose. The wives kept their husbands brass curling stone handle on the mantelpiece, brightly polished until the next time it was needed.
Outdoor curling was very popular in Scotland between the sixteenth and the nineteenth centuries as the climate provided good ice conditions every winter. Scotland is home to the international governing body for curling, the World Curling Federation, Perth, which originated as a committee of the Royal Caledonian Curling Club, the mother club of curling. Today the game is most firmly established in Canada, having been taken there by Scottish emigrants. The Royal Montreal Curling Club, the oldest active athletic club of any kind in North Americawas established in 1807. The first curling club in the United States began in 1830, and the game was introduced to Switzerland and Sweden before the end of the nineteenth century, also by Scots. Today, curling is played all over Europe and has spread to Japan, Australia, New Zealand, China and Korea.
The first world curling championship in the sport was limited to men and was known as the "Scotch Cup" held in Falkirk and Edinburgh, Scotland, in 1959. The first world title was won by the Canadian team from Regina, Saskatchewan, skipped by Ernie Richardson. (The skip is the team member who calls the shots, see below.)
The first curling club in the United States was organized in 1831 only thirty miles from Detroit at Orchard Lake, Michigan. Called the 'Orchard Lake Curling Club', the club used hickory block 'stones'. A Detroit Curling Club was started back in 1840 when Michigan only had a population of 212,000 and had only been in the Union for three years. About this time an organization called the 'Thistle Club' was founded and, curling being a winter sport, was played when the ice was right on the Detroit River at the foot of Joseph Campau, on the bay, and at the old Recreation Park. These clubs became the 'Granite Club' and in 1885 the present Detroit Curling Club was organized.
The curling sheet, by World Curling Federation standards, is an area of ice 146 feet (44.50 m) in length by 14 feet 2 inches (4.32 m) to 16 feet 5 inches (5.00 m) in width, carefully prepared to be as close to level as possible. The ice is most often artificially refrigerated by means of a refrigeration plant. The ice plant cools a brine solution, which runs lengthwise in numerous pipes under the curling sheet. A key part of the preparation of the playing surface is the spraying of water droplets onto the level ice. These water droplets are called pebble. Due to the friction between the stone and pebble, the stone turns to the inside or outside, causing the stone to 'curl'. The amount of curl can change during a game as the pebble wears. The surface of the ice is maintained at a temperature near 23°F (−5°C).
Making and maintaining perfect ice conditions at a curling club is as much an art as a science. Most curling clubs have an ice maker whose main job is to care for the ice. At the major curling championships, ice maintenance is extremely important. Well known professional ice makers Shorty Jenkins, Hans Wuthrich and Dave Merklinger reside in Canada. Large events such as the Brier or other national championships are typically held in an arena which presents a challenge to the ice maker as they must constantly monitor and adjust the ice and air temperatures as well as air humidity levels to ensure a consistent playing surface. It is common for each sheet of ice to have multiple sensors embedded to monitor surface temperature as well as probes set up in the seating area to monitor humidity and in the compressor room to monitor brine supply and return temperatures.
On the sheet, a 12-foot (3.66 m) wide set of concentric rings, called the house, is painted near each end of the rink. The centre of the house is marked by the junction of two lines that divide the house into quarters and is known as the button. The two lines are the centre line, which is drawn lengthwise down the centre of the sheet, and the tee line, drawn 16 feet (4.88 m) from the backboard and parallel to it. Two other lines, the hoglines, are drawn parallel to each backboard and 37 feet (11.28 m) from it.
The rings that surround the button are defined by their diameter as the four-foot, eight-foot, and twelve-foot rings. They are usually distinguished by colour. The inner rings are merely a visual aid for judging which stone is closer to the centre; they do not affect scoring; however, a stone that is not at least touching the outside of the ring (i.e. more than from the centre) is not in the house and therefore does not score (see below).
Twelve feet behind the button are located the hacks. A hack is a device used to provide traction to the curler making a shot; the curler places the foot he or she will push off with in the hack. On indoor rinks there are usually two fixed hacks, rubber-lined holes, one on each side of the centre line with the inside edge no more than three inches (7.6 cm) from the centre line and the front edge on the hack line. A single moveable hack may also be used.
After each end, the thirds for both teams must reach an agreement about which team scored and how many points. If there is a disagreement, or uncertainty, the thirds will call an official to see which ones are closer. If no officials are present the thirds will measure themselves. At this time, only the thirds are allowed in the house. In major tournaments, the scorekeeping is left to an official. Depending on the tradition, when the third's team scores, the third will record it on the score-board.
Depending on the tradition, the third may flip a coin with the opposing third to determine who will have last rock (hammer) advantage at the beginning of a game. (In some areas, namely the Ottawa area, the lead does this) The winner of the toss has the option to pick either last rock, or the colour of the rocks they wish to play with. In major tournaments, these decisions are usually made beforehand.
The skip rarely does any sweeping, except in the house and behind the tee line. The skip is required to stay out of the playing area when it is the other team's turn, but he or she is allowed to sweep stones in motion behind the tee line as a result of their shot. (In International rules, the player in charge of the house is the only player allowed to sweep their opponent's stones behind the tee-line. For most of the end that is the skip, but when the skip is throwing the vice-skip takes charge of the house.
There is a movement afoot in Winnipeg, Manitoba, however, advocating against traditional skip-only naming. A team based out of the Fort Rouge Curling Club is calling themselves The Right Offs. Their belief is that naming the team after the skip alone is offensive to the equally important front-end.
When curling, players normally wear specially designed shoes. The sole of one shoe has a thin strip of Teflon or another type of smooth surface, called a slider. As an alternative, inexpensive sliders can be purchased and attached to any shoe by means of an elastic strap.
The slider enables curlers to slide out of the hack when delivering a rock. Left-handed curlers wear this shoe on their right foot, while right-handed curlers wear it on their left. The other shoe has a thin layer of rubber to maximize traction on the ice. Another piece of footwear is the gripper, which can be put over and taken off the shoe with the slippery surface. This is also usually made of rubber. This piece of equipment is needed when a player is sweeping, and needs traction with both feet.
Casual players may wear running shoes and improvise a slider by applying electrical tape or similar to their off foot.
In earlier days, brooms were made of corn strands and were similar to household brooms. Brushes were used primarily by elderly curlers as a substitute for corn brooms. Today, brushes have replaced traditional corn brooms at every level of curling, but are universally referred to as brooms. Curling brushes may have fabric, hog-hair, or horse-hair heads. Most modern broomsticks are now made of materials such as carbon fiber, allowing faster sweeping. Brooms are also used by most curlers as a balancing aid during delivery of the stone.
The curling stone, or rock, weighs a maximum of 44 lb (20 kg). It has a maximum allowable circumference of 36 inches (0.9 m). A stone may be a maximum of 4.5 inches (11.43 cm) in height not including the handle. The handle is attached to the stone by means of a bolt, which runs vertically through a hole in the center of the stone. The handle allows the rock to be gripped and rotated upon release. When the rock is thrown with the right hand, clockwise rotation is referred to as an in-turn. Counter-clockwise rotation is referred to as an out-turn. The opposites are true if the rock is thrown with the left hand. The handles are coloured to differentiate the rocks belonging to each team. Two popular colours in major tournaments are red and yellow. However, the most common club rock colours are red and blue, although often they will be the "club colours". The handle may be of the 'Eye on the hog' variety for detecting hog line violations.
The top and bottom of a curling stone are concave. The surface in contact with the ice, known as the running surface, is a circle ¼ to ½ inch (6 to 12 mm) thick. This narrow running surface is where the ice and the stone interact. On properly prepared ice, the rock's path will bend (curl) in the direction the front edge of the rock is turning, especially toward the end of its motion. The degree of curl depends on several factors, including the preparation of the ice and the flattening of common paths to the house during the game. Ice on which the rocks curl well is said to be swingy. Curling stones are reversed (i.e. the running surface on the top is placed on the bottom) every eight to ten years.
The Scots in particular believe that the best quality curling stones are made from a specific type of granite called "Ailsite", found on the Ailsa Craig, an island off the Ayrshire coast. According to the Scottish Curling Stone Company, Ailsite has very low water absorption which prevents the action of freezing and melting water from eroding the stone. In the past, most curling stones were made from this granite. However, the island is now a wildlife reserve, and is no longer used for quarrying. Because of the particular rarity of Ailsite, costs for curling stones can reach as much as US$1,500 for the best stones. Many curling clubs use a lower grade stone that can cost upwards of $500. There are also stones which use a disc with a running surface of Ailsite attached below another type of granite. Very informal neighbourhood curling clubs with limited resources may make cylindrical "curling stones" out of concrete-filled cans. Kays of Scotland has been making curling stones since 1851 and has the exclusive rights to Ailsa Craig granite as granted by the Marquess of Ailsa, whose family has owned the island since 1560. The last "harvest" of Ailsa Craig granite by Kays took place in 2002, yielding 200 ton (note, Kays' statement is that they harvested 1500 ton, sufficient to fill anticipated orders through the year 2020 at least ). Kays of Scotland has been the exclusive manufacturer of curling stones for all three Olympics where curling has been a medal sport Pictures of the official Olympic curling stone are available on Kays' web site.
Although the rock is designed to be delivered by players grasping the handle as they slide down the ice, a special "delivery stick" may be used by players incapable of delivering the rock in this fashion. Such a stick is designed to attach to the handle so that it can be released without requiring the player to place a hand on the handle in a crouched position. This allows the game to be played by players with disabilities, as well as those unable to crouch comfortably. According to the Canadian Curling Association Rules of Curling, "The use of a curling aid commonly referred to as a 'delivery stick' which enables the player to deliver a stone without placing a hand on the handle is considered acceptable." The stone is about 40 lbs.
It is not uncommon at any level for a losing team to terminate the match before all ends are completed if it believes it no longer has a realistic chance of winning. Playoff games at national and world championships require eight ends to be completed before allowing a losing team to concede in this manner. Competitive games will usually end once the losing team is "run out of rocks" – that is, once it has fewer stones in play and/or available for play than the number of points needed to tie the game in the final end.
In international competition each side is given 73 minutes to complete all of their throws. Each team is also allowed two 60 second timeouts per ten end game. If extra ends are required each team is allowed 10 minutes of playing time to complete their throws and one added 60 second timeout for each extra end.
The rule concerning releasing the rock before the hogline is rarely enforced in club play, unless abuse of the rule occurs. In major tournaments, the "eye on the hog" sensor in the rock will indicate whether the rock has been legally thrown or not. If the lights on the rock go red, the rock will be immediately pulled from play instead of waiting for the rock to come to rest.
While the first three players throw their rocks, the skip remains at the far end of the ice to guide the players. While the skip is throwing, the third takes this role. Thus, each time a rock is thrown, there is one player throwing the rock, and another player at the far end. The other two players may choose to sweep in front of the rock (see sweeping, below).
When delivering the rock, it is important to remember that the momentum behind how much weight is applied to the rock depends on how much leg drive the delivery has. It is usually not wise to push the rock with the arm, unless absolutely necessary. When in the hack, one must crouch down with the body lined up and shoulders square with the skip's broom at the other end. While in the hack, one may hold a broom out for balance. Different curlers hold their broom out in many different fashions. The broom is held in the hand opposite from the rock, and should be positioned so that the non-sweeping side of the broom is against the ice. This prevents drag which would be caused by the soft head of the broom dragging against the ice.
Before any delivery, it is important to ensure that the running surface of the rock is clean, and that the area around you is clean as well. This is achieved by wiping the running surface of the rock with either your hand or with the broom, and then cleaning the area around you with the broom. The reason for this is that any dirt in the area or on the bottom of a rock could alter the trajectory of it and ruin the shot. When this happens, this is called a "pick".
After cleaning the rock, the next step is to know what rotation, or turn, to put on the rock. The skip will usually tell the thrower this information. The thrower will then place the handle of the rock generally at either a "two o'clock" or a "ten o'clock" position. When delivering the rock, the thrower will turn the rock from one of these two positions toward the "twelve o'clock" position before releasing it. A rock turned from ten o'clock to twelve will spin clockwise and curl to the right, and a rock turned from two o'clock to twelve will have the opposite effect. A generally desired rate of turn is about two and a half rotations before coming to a rest.
Once the thrower knows the turn to give the rock, the thrower will place the rock in front of his or her toe in the hack. At this point the thrower will then start his or her delivery. This begins by slightly rising from the hack, and moving the rock back to one's toe. This is the beginning of a pendulum movement that will determine the force given to the rock. Some older curlers will actually raise the rock in this backward movement, as this is what they are accustomed to. The forward thrust of the delivery comes next. The thrower moves his or her slider-foot in front of the other foot while keeping the rock ahead of him. The thrower then lunges out from the hack. The more thrust from this lunge, the more power or "weight" the rock will have. When lunging out, the gripper-foot will drag behind the thrower. When lunging out, it is important to push as precisely as possible in the direction of the skip's broom at the other end, so that the "line" of the rock is accurate. The rock should be released before the thrower's momentum wanes at which point the thrower imparts the appropriate curl, keeping in mind the stone should be released before the first hog-line.
The amount of weight given to the rock will also be told to the thrower by the skip at the other end. This usually occurs by the skip tapping the ice with his broom where he or she wants the rock to be delivered. In the case of a take-out or a tap, the skip will tap the rock that he or she wants removed or tapped. Generally, the skip will not hold the broom in the same place he expects the rock to stop or hit; instead, the skip estimates how much the rock will curl as it travels down the ice and holds the broom where he believes the thrower will have to aim in order to hit the target.
One of the interesting strategy aspects of curling is knowing when to sweep. When swept, a rock will usually travel both farther and straighter. In some situations, one of the two is often not desirable (for example, a rock may have too much weight, but needs sweeping to prevent curling into a guard), and the team must decide which is better: getting by the guard but traveling too far, or hitting the guard.
Much of the yelling that goes on during a curling game is the skip calling the line of the shot. The skip evaluates the path of the rock and calls to the sweepers to sweep as necessary to hold the rock straight. The sweepers themselves are responsible for judging the weight of the rock and ensuring the length of travel is correct. Simultaneously, the sweepers must communicate the weight (speed) of the rock back to the skip. Some teams use stop watch timing, from back line to the nearest hog line as a sweeping aid. Many teams use the "Number System," where the playable area is divided into ten zones, each assigned a number, and these numbers are used to communicate where the sweepers estimate the rock will stop.
Usually, the two sweepers will be on opposite sides of the rock's path, although depending on which side people's strengths are, this may not always be the case. Speed and pressure are vital to sweeping. In gripping the broom, one hand should be one third of the way from the top (non-brush end) of the handle while the other hand should be one third of the way from the head of the broom. The angle of the broom to the ice should be so that the most force possible can be exerted on the ice. The precise amount of pressure may vary from relatively light brushing "just cleaning" (to ensure debris is not in the way) to maximum-pressure scrubbing.
Sweeping can be done anywhere on the ice up to the "tee-line", as long as it is only for your own team's rock. Once your team's rock crosses the tee-line, only one player may sweep it. Additionally, when an opposing rock crosses the tee-line, one player from your team is allowed to sweep it. This is the only case that a rock may be swept by an opposing team member. In international rules, this player must be the skip, or if the skip is throwing, then the third.
Possibly the most notable current front end (the lead and second of a team) sweeping duo are Scott Pfeifer and Marcel Rocque, nicknamed "Huff and Puff," of Team Ferbey. Many men's teams at the championship level in Canada frequently have a front end who are significantly younger and often in greater physical condition than the skip, acknowledging the physically demanding nature of sweeping and the changes in ice-making and equipment which have made effective and powerful sweeping of greater importance to the game.
The result of a touched stone varies based on which team touched the stone, whether the stone was being delivered, stationary, or set in motion by another stone, and whether touching the stone impacted the positions of other stones. Rules also vary across different governing bodies.
Per Canadian Curling Association (CCA) rules, if a moving stone is touched by the team to which it belongs, all rocks must come to a rest before the offending team may declare that the violation occurred. At this time, the non-offending skip may decide whether to leave all stones where they stopped, or remove the touched stone from play and place any other stones in their original positions. If the incident occurs after the stone has crossed the far hogline, he or she may also opt to move the rock and any stones it would have affected to where he or she thinks they would have ended up had the rock not been burned. Under these rules, it is also a violation for the delivering player to touch the stone once he has released the handle even if the stone has not yet crossed the near hogline.
In the World Curling Federation (WCF) rules, if a moving stone is touched by a member of the team to which it belongs before it reaches the far hogline, the offending team should declare the violation immediately, and the stone is removed from play immediately. If the infraction occurs after the stone has crossed the far hogline, the skip of the opposing team may leave the stones where they stop, remove the touched stone from play and reset any stones that were moved, or placing the touched stone and any stones it would have affected where he thinks they would have stopped.
Under CCA rules, if a delivered stone is touched by a member of the opposing team, the non-offending skip may leave the stones where they end up, place them where he believes they would have ended up had the infraction not occurred, or place all stones in their prior positions and have the touched stone delivered again.
In WCF play, if such a violation occurs prior to the delivered stone crossing the far hogline, the touched stone may only be re-delivered. If the violation occurs after the delivered stone crosses the far hogline, the skip of the non-offending team may only place the stones where he believes they would have stopped had the infraction not occurred.
In the CCA if any other stone set in motion is touched by the opposing team, the skip of the non-offending team may choose to leave the stones where they stop or place them where he believes they would have stopped had the infraction not occurred. In the WCF, the skip of the non-offending team may only place the stones where he believes they would have stopped had the infraction not occurred.
Under both CCA and WCF rules, if a stationary stone is touched in a way that would have impacted the result of a moving stone, the skip of the non-offending team may choose to leave the touched stone and any impacted stones where they end up, put the impacted stones in their original position and remove the stone whose course would have been altered from play (not necessarily the touched stone), or placing all impacted stones where he believes they would have stopped had the infraction not occurred. If a touched stationary stone would not have impacted the result of a moving stone, the touched stone is simply returned to where it was before being touched.
The three-rock rule, known as the Modified Moncton Rule, was developed from a suggestion made by Russ Howard for a cashpiel (with the richest prize ever awarded at the time in a tournament) in Moncton, New Brunswick in 1991. "Howard's Rule" (also known as the Moncton Rule), used for the tournament and based on a practice drill his team used, had the first four rocks in play unable to be removed no matter where they were at any time during the end. The Modified Moncton Rule was quickly adopted in Canada, while the four-rock Free Guard Zone was adopted by other countries and for international competition. After several years of having the Modified Moncton Rule used for the Canadian championships and the winners then having to adjust to the 4 rock rule in the World Championships, the Canadian Curling Association adopted the now-standard Free Guard Zone.
This rule, a relatively recent addition to curling, was added in response to a strategy of "peeling" opponents' guard stones (knocking them out of play at an angle that caused the shooter's stone to also roll out of play, leaving no stones on the ice). A team in the lead would often employ this strategy during the game. By knocking all stones out, the opponents could at best score one point (if they had the hammer). Alternatively, the team with the hammer could peel rock after rock, which would blank the end, keeping the last rock advantage for another end. This strategy had developed (mostly in Canada) as ice-makers had become skilled at creating a predictable ice surface and the adoption of brushes allowed greater control over the rock. While a sound strategy, this made for an unexciting game. The 1990 Brier was considered by many curling fans as boring to watch because of the near-constant peeling and the quick adoption of the Free Guard Zone the following year reflected how disliked this aspect of the game had become.
One strategy that has been developed by curlers in response to the free guard zone (Kevin Martin from Alberta as one of the best examples) is the "tick" game, where a shot is made attempting to knock ("tick") the guard to the side, far enough that it is difficult or impossible to use but still remaining in play while the shot itself goes out of play. The effect is functionally identically to peeling the guard but significantly harder as a shot which hits the guard too hard knocking it out of play results in it being replaced, while not hitting it hard enough can result in it still being tactically useful for the opposition. There's also a greater chance of the shot missing the guard entirely due to the greater accuracy required to make the shot. Due to the difficulty of making this type of shot only the best teams will normally attempt it, and it does not dominate the game the way the peel formerly did.
The score is marked on a scoreboard, of which there are two types. One is the baseball type scoreboard, which is usually used for televised games. On this scoreboard the ends are marked by columns 1 through 10 (or 11 for the possibility of an extra end to break ties) plus an additional column for the total. Below this are two rows — one for each team. The number of points each team gets in an end is marked this way.
The other form of scoreboard is the one used in most curling clubs (see photo). It is set up in the same way, except the numbered row indicates a team's progress in scoring points rather than marking ends, and it can be found between the rows for the team. The numbers placed are indicative of the end. If the red team scores 3 points in the first end (called a three-ender), then a one (indicating the first end) is placed beside the number three in the red row. If they score two more in the second end, then a two will be placed beside the five in the red row indicating that the red team has five points in total (3+2). This scoreboard works because only one team can get points in an end. However, some confusion can exist if no team gets points in an end. This is called a blank end and the end number usually goes in the furthest column on the right in the row of the team who has the hammer (last rock advantage), or on a special spot for blank ends.
The following example illustrates the difference between the "Baseball" style scoreboard used for televised curling matches and the style used at most curling clubs. The example illustrates the men's final at the 2006 Winter Olympics.
"Curling club" scoreboard
Eight points (all the rocks thrown by one team counting) is the highest possible score possible in an end, and is known as an "eight-ender". Scoring an eight-ender against a relatively competent team is very difficult, in curling considered the equivalent of pitching a perfect game in baseball. Probably the most well known 8-ender came at the 2006 Players' Championships. Future (2007) World Champion, Kelly Scott scored eight points in one of her games against 1998 World bronze medalist Cathy King.
Unlike other sports, there is not a negative connotation associated with conceding in curling. In fact, in some situations it is expected, and it is a breach of etiquette (or at least looked down upon) to keep playing when the game is well out of reach.
Strategy in an end of curling depends on the circumstances. It depends on the team's skill, the opponents' skill, the conditions of the ice, the score of the game, how many ends remain, and whether the team has last rock advantage. A team may play an end aggressively- that is to have a lot of rocks in play by throwing mostly draws. This makes for an exciting game, but is very risky. However, the reward can be very great. A team may also wish to play an end defensively. This means throwing a lot of hits preventing a lot of rocks in play. This is generally considered to be less exciting, and is less risky. A good drawing team will usually opt to play aggressively, while a good hitting team will opt to play defensively.
If a team does not have the hammer in an end, they will opt to try and clog up the "four foot" (the four foot wide area surrounding the centre line) so as to prevent the opposing team from being able to access the button. This can be done by throwing "centre line" guards (rocks in front of the house touching the centre line). These can be tapped into the house later, or drawn around. If a team has hammer, they want to keep this four foot zone free of rocks, so they have access to the button area at all times. A team with hammer may throw up a "corner guard" as their first rock of an end to utilize the free guard zone. A corner guard is a rock in front of the house that is not in the four foot zone. Corner guards are key for a team to score two points in an end, because they can either draw around it later, or hit and roll behind it making the opposing team's shot to remove it more difficult.
Ideally, the strategy in an end for a team with hammer is to score two points or more. Scoring one point is often a wasted opportunity, as they will then lose last rock advantage for the next end. If a team can't score two points, they will often attempt to "blank an end" by removing any left over opposition rocks and rolling out, or if there are no opposition rocks, just throwing the rock through the house so that no team scores any points, and the team with the hammer can try again the next end to score two or more with it. Generally, a team without hammer would want to either force the team with hammer to only one point (so that they can get hammer back) or "steal" the end by scoring one or more points of their own.
Generally, the larger the lead a team will have in a game, the more defensively they should play. By hitting all of your opponent's stones, it removes opportunities from them getting multiple points, therefore defending your lead. If your lead is quite comfortable, leaving your own rocks in play can also be dangerous. Guards can be drawn around by the other team and rocks in the house can be tapped back (if they are in front of the tee-line) or frozen on to (if they are behind the tee line). A frozen rock is difficult to remove, because it is "frozen" (in front of and touching) to the opponents rock. At this point, a team will opt for "peels", meaning that the rocks they throw will be to not only hit their opposition stones, but to roll out of play as well. Peels are hits that are thrown with the most amount of power.
Curling is played in many countries including the United States, United Kingdom (especially Scotland), Norway, Sweden, Switzerland, Denmark, Finland and Japan, all of which compete in the world championships.
Curling is particularly popular in Canada. Improvements in ice making and changes in the rules to increase scoring and promote complex strategy have increased the already high popularity of the sport in Canada, and large television audiences watch annual curling telecasts, especially the Scott Tournament of Hearts (the national championship for women), the Tim Hortons Brier (the national championship for men), and the women's and men's world championships.
Despite the Canadian province of Manitoba's small population, teams from that province have won the Brier more times than teams from any other province. The Tournament of Hearts and the Brier are contested by provincial and territorial champions, and the world championships by national champions.
Curling is the provincial sport of Saskatchewan, home of some of the most famous curlers. Ernie Richardson and his family team dominated Canadian and international curling during the late 1950s and early 1960s and are generally conceded to be the best male curlers of all time. Sandra Schmirler led her team to the first ever gold medal in women's curling in the 1998 Winter Olympics. When she died two years later from cancer, over 15,000 people attended her funeral, and it was broadcast on national television.
As noted above in the game play section, it is not uncommon for a team to concede a curling match after it believes it no longer has a reasonable chance of winning but before all ends are completed. Concession is an honorable act and does not carry the stigma associated with quitting. To concede a match, the losing team removes their curling gloves (if they wear them) and offer congratulatory handshakes to the winning team. Thanks and wishes of future good luck are usually exchanged between the teams.
Another measure of rock speed is known as "hog-to-hog" and can also be measured in seconds. This time is the time the rock takes from the moment it crosses the near hog line till it crosses the far hog line. If this number is lower, the rock is moving faster, so again low numbers mean more speed. The ice in a match will be somewhat consistent and thus this measure of speed can also be used to measure how far down the ice the rock will travel. Once it is determined that a rock taking (for example) 9 seconds to go from hog line to hog line will stop on the tee line, the curler can know that if the hog-to-hog time is matched by a future stone, that stone will likely stop at approximately the same location. As an example, on keen ice, common times might be 16 seconds for guards, 14 seconds for draws, and 9 seconds for peel weight.
A third measurement system is from back line to hog line at the throwing end. This is used principally by sweepers to get an initial sense of the weight of a stone. As an example, on keen ice, common times might be 4.0 seconds for guards, 3.8 seconds for draws, 3.2 for normal hit weight, and 2.9 seconds for peel weight.