[nfbwatlk] curling

[Albert Sanchez]

Hi All
I thought that you all might find the following information interesting if you, like Gerrie and I, have been watching the Olympics and the Curling matches, Enjoy, A.S.

Curling 
 
Highest governing body World Curling Federation 
First played Approximately late medieval Scotland 
Characteristics 
Team members 4 per team (2 in Mixed Doubles) 
Venue Curling sheet 
Olympic * 1924 (Retroactively made official in 2006).
·  Demonstration sport in 1932, 1988 and 1992.
·  Officially added in 1998. 
Curling is a team Olympic sport in which stones are slid across a sheet of carefully prepared ice towards a target area. It is related to lawn bowling, boule and shuffleboard.
Two teams of four players take turns sliding heavy, polished blue hone granite stones across the ice towards the house (a circular target marked on the ice). The purpose is to complete each end (delivery of eight or ten stones [depending on recreational or competitive play] for each team) with the team's stones closer to the centre of the house than the other team's stones. Two sweepers with brooms or brushes accompany each stone and use stopwatches and their best judgment, along with direction from their teammates, to help direct the stones to their resting place, but without touching the stones.
Contents
·  1 Origins and history
·  1.1 Olympic curling
·  2 Playing surface
·  3 Equipment
·  3.1 Shoes
·  3.2 Broom (brush)
·  3.3 Curling stone (rock)
·  3.4 Other equipment
·  3.5 Specialized equipment
·  4 Gameplay
·  4.1 Throwing
·  4.1.1 Delivering the stone
·  4.1.2 Special needs in curling
·  4.2 Sweeping
·  4.2.1 Touched stones
·  4.3 Types of shots
·  4.4 Free guard zone
·  4.5 Hammer
·  4.6 Scoring
·  4.7 Conceding a game
·  4.8 Dispute resolution
·  4.9 Strategy
·  5 Curling culture
·  5.1 An amateur sport
·  5.2 Good sportsmanship
·  6 Additional information
·  6.1 By the numbers
·  7 Terminology
·  8 See also
·  9 Champions and major championships
·  10 Notable curling clubs
·  11 References
·  12 External links 
Origins and history


Men curling in Ontario in 1909
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.

Purpose-built curling pond at Colzium, Kilsyth
That the game of curling was already in existence in Scotland in the early 16th century is 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; it 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 × 250 metres in size, though this is now very seldom in condition for curling because of 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 verbal noun curling is formed from the Scots (and English) verb curl which describes the motion of the stone.

Group of people curling on a lake in Dartmouth, Nova Scotia, Canada, ca. 1897
In the early history of curling, the playing stones (or rocks) were simply flat-bottomed river stones that were sometimes notched or shaped; the thrower had little control over the stone, 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. Many a wife would keep her husband's 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 16th and 19th centuries, as the climates 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 established sports club still active in North America, was 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 19th century, also by Scots. Today, curling is played all over Europe and has spread to Japan, Australia, New Zealand, China, and Korea.

A curling match at Eglinton Castle, Ayrshire, Scotland in 1860. The Curling House is located to the left of the picture.
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.)

A Curling House near Stewarton in Ayrshire, Scotland, now converted into a dwelling
The first curling club in the United States was organized in 1830 only 30 miles from Detroit, at Orchard Lake, Michigan. Called the Orchard Lake Curling Club, the club used hickory block "stones".
The 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 suitable 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.

Olympic curling
Curling has been an official sport in the Winter Olympic Games since the 1998 Winter Olympics. In February 2006, the International Olympic Committee retroactively decided that the curling competition from the 1924 Winter Olympics (originally called Semaine des Sports d'Hiver, or International Winter Sports Week) would be considered official Olympic events and no longer be considered demonstration events. Thus, the first Olympic medals in curling, which at the time was played outside, were awarded for the 1924 Winter Games, with the gold medal won by Great Britain and Ireland, two silver medals by Sweden, and the bronze by France. A demonstration tournament was also held during the 1932 Winter Olympic Games between four teams from Canada and four teams from the United States, with Canada winning 12 games to 4.

Playing surface

The playing area in curling is shown here. Stones must land between the hog line (bottom of photo) and the back line (behind the rings) and may not contact boards or out lines (on the sides) at any time during travel.
The curling sheet, by World Curling Federation standards, is an area of ice 146 to 150 feet (45 to 46 m) in length by 14.5 to 16.5 feet (4.4 to 5.0 m) in width, carefully prepared to be as close to level as possible. The ice is most often frozen by means of a refrigeration plant that cools a brine solution running lengthwise in numerous pipes under the curling sheet. A key part of the preparation of the playing surface is the spraying of water droplets, called "pebble", onto the level ice. Because of 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 around 23 °F (-5 °C).
Making and maintaining perfect ice conditions at a curling club is as much art as 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. Large events, such as the Brier or other national championships, are typically held in an arena that 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 in order 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).

Players must push out of the hack to deliver their stones; whether they are left- or right-handed determines which foot they use.
On the sheet, a 12-foot (3.7 m) wide set of concentric rings, called the house, is placed (painted or by laying down vinyl rings) near each end of the rink. The centre of the house, known as the button, is marked by the junction of two lines that divide the house into quarters. The two lines are the centre line, which is drawn lengthwise down the centre of the sheet, and the tee line, drawn 16 feet (4.9 m) from the backboard and parallel to it. Two other lines—the hog lines—are drawn parallel to each backboard and 37 feet (11 m) from them.
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 12-foot (3.7 m) ring (i.e., more than 6 feet (1.8 m) from the centre) is not in the house and therefore does not score (see below).
Located 12 feet behind the button are the hacks. A hack is a device used to provide traction to the curler making a shot; the curler places the foot with which he or she will push-off 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 3 inches (76 mm) from the centre line and the front edge on the hack line. A single moveable hack may also be used.


Graphical depiction of a curling sheet. The thick lines are the hog lines, and the tee lines run through each of the targets (the houses).

Equipment

Shoes

Curling shoes:
The slider shoe (center), with its thin Teflon surface, is worn during delivery to slide on the ice; a slip-on gripper (left) is worn over the slider at other times. The other shoe (right) has a rough surface to give its wearer traction on the ice. Higher-end shoes are often made of leather, while lower-end shoes are often made of vinyl, or canvas.
A casual player may wear running shoes and improvise a slider by applying electrical tape (or something similar) to his or her off foot. Step-on or slip-on Teflon sliders are also available.

The curling broom is used to sweep the ice surface in front of the stone.
Broom (brush)
The curling broom is used to sweep the ice surface in front of the stone (see sweeping under Gameplay below). 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 horsehair heads. Most top quality modern broomsticks are now made of materials such as carbon fiber, allowing faster sweeping; lower-end brooms are often made of fiberglass. Brooms may also be used as a balancing aid during delivery of the stone.

Curling stone (rock)

The curling stone or rock is made of granite.
The curling stone, as defined by the World Curling Federation, is circular in shape and weighs between 38 and 44 pounds (17 and 20 kg) with a handle and bolt attached. The stone has a maximum allowable circumference of 36 inches (910 mm). A stone must be a minimum of 4.5 inches (110 mm) in height. The handle is attached to the stone by means of a bolt that runs vertically through a hole in the centre of the stone. The handle allows the stone to be gripped and rotated upon release. When the stone is thrown with the right hand, clockwise rotation is referred to as an in-turn, as the elbow turns into the body as the clockwise rotation is imparted on release; counterclockwise rotation is referred to as an out-turn. The opposites are true if the stone is thrown with the left hand. The handles are coloured to differentiate the stones belonging to each team. Two popular colours in major tournaments are red and yellow. 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 0.25 to 0.50 inches (6.3 to 13 mm) thick. This narrow running surface is where the ice and the stone interact. On properly prepared ice, the stone's path will bend (curl) in the direction the front edge of the stone 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 stones curl well is said to be swingy.

An old-style curling stone
The Scots, in particular, believe that the best-quality curling stones are made from a specific type of granite called "ailsite", found on 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 that 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 or bowls. Kays of Scotland has been making curling stones since 1851 and has the exclusive rights to Ailsa Craig granite, 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 tons (note: Kays' statement is that they harvested 1,500 tons, sufficient to fill anticipated orders through at least 2020). 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' website.

 Other equipment
Other types of equipment a curler may utilize include:
1. Curling pants, made to be stretchy to accommodate the curling delivery.
2. A stopwatch to time the stones while sweeping to get a feel of the speed of the stone. Stopwatches can be attached either to clothing or the broom itself.
3. Curling gloves and mittens, to keep the hands warm and improve grip on the broom.
Specialized equipment
A special handle for stones has recently been developed, called the "eye on the hog", which integrates electronics to ensure stone release before crossing the hog line. The handle is coated in metallic paint, and the electronics detects the natural human electric charge of the thrower's hand to determine if his or her hand is in contact, and an electric field at the hog line detects it. Lights at the base of the handle indicate whether contact was maintained past the line. This eliminates the chance of human error (eliminating the game's most frequent cause of controversy), also eliminating the need for hog line officials. The downside is that the equipment costs around $650 a piece, which multiplies quickly with the number of stones and sheets of ice in a tournament. Hence, it's used mostly in high-level national and international competition, such as the Winter Olympics.
Although the stone is designed to be delivered by players grasping the handle as they slide along the ice, a special "delivery stick" may be used by players incapable of delivering the stone 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 by 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" in club play. This device is not permitted in championship playdowns.

Gameplay
A competitive game usually consists of 10 ends. Recreational games are most commonly eight ends. An end consists of each player from both teams throwing two stones down the sheet with the players on each side alternating shots, for a total of 16 stones. If the teams are tied at the completion of 10 ends, play continues for as many ends as may be required to break the tie. The winner is the team with the highest score after all ends have been completed (see Scoring below).
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 has "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 its throws. Each team is also allowed two 60-second timeouts per 10-end game. If extra ends are required, each team is allowed 10 minutes of playing time to complete its throws and one added 60-second timeout for each extra end.

Throwing
When throwing the stone, the player must release it before the front edge of the curling stone reaches the near hog line (players usually slide while releasing their shots) and it must completely cross the far hog line; otherwise, the stone is removed from play (hogged). An exception is made if a thrown stone fails to come to rest beyond the far hog line after striking a stone in play (e.g., rebounding back off a stone just past the hog line).
The rule concerning releasing the stone before the hog line is rarely enforced in club play, unless abuse of the rule occurs. In major tournaments, the "eye on the hog" sensor in the stone will indicate whether the stone has been legally thrown or not. If the lights on the stone turn red, the stone will be immediately pulled from play instead of waiting for the stone to come to rest.
While the first three players throw their stone, 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 stone is thrown, there is one player throwing the stone and another player at the far end. The other two players may choose to sweep in front of the stone (see Sweeping, below).
Delivering the stone
The process of throwing a stone is known as the delivery. While not compulsory, most curlers deliver the stone from sliding out from the hack. When sliding out, one shoe (the one with the non-slippery sole) is positioned against one of the hacks (a position referred to as being in the hack). For a right-handed curler, this means starting with the right foot in the left hack, and vice-versa for a left-handed curler.
When delivering the stone, it is important to remember that the momentum behind how much "weight" (velocity) is applied to the stone depends on how much leg drive the delivery has. It is usually not wise to push the stone 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 brooms out in many different fashions. The broom is held in the hand opposite from the stone and should be positioned so that the non-sweeping side of the broom is against the ice. This prevents drag 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 stone is clean and that the surrounding area is clean as well. This is achieved by wiping the running surface of the stone with either the player's hand or with the broom and then cleaning the area with the broom. The reason for this is that any dirt in the area or on the bottom of a stone could alter the trajectory of it and ruin the shot. When this happens, it is called a "pick up" or simply a "pick".
After cleaning the stone, the next step is to know what rotation, or turn, to put on the stone. The skip will usually tell the thrower this information. Considering the top of the stop as if it were a clock, the thrower will then place the handle of the stone generally at either a "two o'clock" or a "ten o'clock" position. When delivering the stone, the thrower will turn the rock from one of these two positions toward the "twelve o'clock" position before releasing it. A stone 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 2½ rotations before coming to a rest.
Once the thrower knows the turn to give the stone, the thrower will place the stone 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 stone back to one's toe. This is the beginning of a pendulum movement that will determine the force given to the stone. Some older curlers will actually raise the stone 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 stone ahead of him. The thrower then lunges out from the hack. The more thrust from this lunge, the more power or "weight" the stone 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 stone is accurate. The stone 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 stone will also be told to the thrower by the skip at the other end. This usually occurs by the skip's tapping the ice with his broom where he or she wants the stone to be delivered. In the case of a take-out or a tap, the skip will tap the stone that he or she wants removed or tapped. Generally, the skip will not hold the broom in the same place he expects the stone to stop or hit; instead, the skip estimates how much the stone 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 stone.

Special needs in curling
Curling has been adapted for wheelchair users and people otherwise unable to throw the stone from the hack. These curlers may use a special device known as a "curler's cue" or "delivery stick". The cue holds on to the handle of the stone and is then pushed along by the curler. At the end of delivery, the curler pulls back on the cue, which releases it from the stone.

Sweeping
When a stone is delivered, it is important that there be two players following the stone so that they are ready to sweep its path if needed. Sweeping is done for two reasons: to make the stone travel farther, and to change the amount of curl. The stones curl more as they slow down, so sweeping early in travel tends to increase distance as well as straighten its path, and sweeping after sideways motion is established can increase the sideways distance. When sweeping, pressure and speed of the brush head are key in slightly increasing the layers of moisture that builds up under the stone.
One of the interesting strategy aspects of curling is knowing when to sweep. When the ice in front of the stone is swept, a stone will usually travel both farther and straighter. In some situations, one of the two is often not desirable (for example, a stone 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 and the sweepers calling the weight. The skip evaluates the path of the stone 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 stone and ensuring the length of travel is correct. Simultaneously, the sweepers must communicate the weight (speed) of the stone back to the skip. Some teams use stopwatch 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 10 zones, each assigned a number, and these numbers are used to communicate where the sweepers estimate the stone will stop.
Usually, the two sweepers will be on opposite sides of the stone'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 one's own team stone. Once the leading edge of the team's stone crosses the tee line, only one player may sweep it. Additionally, when an opposing stone crosses the tee line, one player from the team is allowed to sweep it. This is the only case that a stone 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.

Touched stones
Occasionally, a player may accidentally touch a stone with his/her broom or a part of his/her body. This is often referred to as "burning" a stone. When a player touches a stone, he/she is expected to call him/herself on it (see Good sportsmanship).
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 affected 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 stone 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 hog line, he or she may also opt to move the "burned" stone and any stones it would have affected to where he or she thinks they would have ended up had the stone 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 hog line.
In 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 hog line, the offending team should declare the violation immediately, and the stone is removed from play. If the infraction occurs after the stone has crossed the far hog line, 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 place 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 hog line, the touched stone may only be redelivered. If the violation occurs after the delivered stone crosses the far hog line, 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 affected the result of a moving stone, the skip of the non-offending team may choose to leave the touched stone and any affected stones where they end up, put the affected stones in their original position and remove the stone whose course would have been altered from play (not necessarily the touched stone), or place all affected stones where he believes they would have stopped had the infraction not occurred. If a touched stationary stone would not have affected the result of a moving stone, the touched stone is simply returned to where it was before being touched.

Types of shots
Essentially, there are three kinds of shots in curling: the guard, the draw, and the takeout. There are many variations of these shots, however. Guards are shots thrown in front of the house, usually to guard shot-rock (stone closest to the button at a certain time) or to make the opposing team's shot difficult. Draws are shots in which the stone is thrown only to reach the house, while takeouts are shots designed to remove stones from play. Choosing which shot to play will determine whether the thrower will use an in-turn or out-turn—for a right-handed person, the clockwise and counter-clockwise rotation of the stone, respectively. Possible guard shots include centre-guard and corner-guards (left and right sides of the centre line). Draw shots include raise (and angle-raise), come-around, and freeze, and takeout shots include peel, hit-and-roll and double. For a more complete listing, look at the complete list Glossary of curling terms.
Free guard zone
Until four stones have been played (two from each side), stones in the free guard zone (those stones left in the area between the hog and tee lines, excluding the house) may not be removed by an opponent's stone. These are known as guard rocks. If the guard rocks are removed, they are replaced to where they were before the shot was thrown, and the opponent's stone is removed from play and cannot be replayed. This rule is known as the four-rock rule or the free guard zone rule (for a while in Canada, a "three-rock rule" was in place, but that rule has been replaced by the four-rock rule).
Originally, the Modified Moncton Rule, was developed from a suggestion made by Russ Howard for a cashspiel (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. This method of play altered slightly and adopted as a Four-rock Free Guard Zone for international competition shortly after. Canada kept to the traditional rules until a three-rock Free Guard Zone rule was adopted, starting in the 1993-94 season. After several years of having the three-rock rule used for the Canadian championships and the winners then having to adjust to the four-rock rule in the World Championships, the Canadian Curling Association adopted the now-standard Free Guard Zone in the 2002-2003 season.
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 is 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 identical to peeling the guard but significantly harder, as a shot that hits the guard too hard (knocking it out of play) results in its being replaced, while not hitting it hard enough can result in its still being tactically useful for the opposition. There's also a greater chance that the shot will miss the guard entirely because of the greater accuracy required to make the shot. Because of 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.

Hammer
Last-rock or last-stone advantage in an end is called the hammer. Before the game, teams typically decide who gets the hammer in the first end either by chance (such as a coin toss) or by a "draw-to-the-button" contest, where a representative of each team shoots a single stone to see who gets closer to the centre of the rings. In all subsequent ends, the hammer belongs to the team that did not score in the preceding end. In the event that neither team scores, the hammer remains with the same team. Naturally, it is easier to score points with the hammer than without; in tournament play, the team with the hammer generally tries to score two or more points. If only one point is possible, the skip will often try to avoid scoring at all in order to retain the hammer until the next end, when two or more points may lie. This is called a blank end. Scoring without the hammer is commonly referred to as stealing, or a steal, and is much more difficult.

Scoring
After both teams have delivered eight stones, the team with the stone closest to the button is awarded one point for each of its own stones that is closer than the opponent's closest stone. Stones that are not in the house (further from the centre than the outer edge of the 12-foot (3.7 m) ring) do not score even if no opponent's stone is closer. A stone is considered in the house if any portion of its edge is over any portion of the 12-foot (3.7 m) ring. Since the bottom of the stone is rounded, a stone just barely in the house will not have any actual contact with the ring, which will pass under the rounded edge of the stone, but it still counts. This type of stone is known as a "biter".

A typical curling scoreboard used at clubs, which use a method of scoring different from the ones used on television
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 teams. The numbers placed are indicative of the end. If the red team scores three points in the first end (called a three-ender), then a 1 (indicating the first end) is placed beside the number 3 in the red row. If they score two more in the second end, then a 2 will be placed beside the 5 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 farthest column on the right in the row of the team that 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.
Baseball-style scoreboard
Team 1 2 3 4 5 6 7 8 9 10 Total 
 Canada 0 2 1 1 0 6 0 0 x x 10 
 Finland 2 0 0 0 1 0 0 1 x x 4 
Curling club-style scoreboard
 Canada  2 3 4      6       
Points 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Blank ends 
 Finland  1 5 8            7 
Eight points (all the rocks thrown by one team counting) is the highest score possible in an end, and is known as an "eight-ender" or "snowman". Scoring an eight-ender against a relatively competent team is very difficult; in curling, it is considered the equivalent of pitching a perfect game in baseball. Probably the most well known snowman 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.

Conceding a game
When a team feels it is impossible or near impossible to win a game, they will usually shake hands with the opposing team to concede defeat. This may occur at any point during the game, but usually happens near the final end. When a game is completed by playing all ends, both teams also shake hands. Hands are also shaken before the game, accompanied by saying "Good curling!" to the opposing team. In the Winter Olympics, a team may concede after finishing any end during a round-robin game, but can only concede after finishing eight ends during the knockout stages.
Unlike other sports, there is no negative connotation associated with conceding in curling. In fact, in many competitions, a team is required to concede when it is mathematically impossible for them to tie a game. In more social situations, it is often considered a breach of etiquette (or at least looked down upon) to keep playing when the game is well out of reach.

Dispute resolution
Most decisions about rules are left to the skips, although in official tournaments, decisions may be left to the officials. However, all scoring disputes are handled by the third, or vice skip. No players other than the third from each team should be in the house while score is being determined. In tournament play, the most frequent circumstance in which a decision has to be made by someone other than the third is the failure of the thirds to agree on which stone is closest to the button. An independent official (supervisor at Canadian and World championships) then measures the distances using a specially designed device that pivots at the centre of the button. When no independent officials are available, the thirds measure the distances.

Strategy

Diagram of the play area in curling, showing the four-foot zone, corner guard, and centre line guard
Strategy in an end of curling depends on the circumstances. It depends on the team's skill, the opponent's skill, the conditions of the ice, the score of the game, how many ends remain, and whether the team has last-stone advantage (i.e. the "hammer"). A team may play an end aggressively; that is, to have a lot of stones 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 stones 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, it 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 accessing 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 stone so that they have access to the button area at all times. A team with the hammer may throw up a "corner guard" as their first stone 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 leftover 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 the opponent's stones, it removes opportunities for their getting multiple points, therefore defending the lead. If the leading team is quite comfortable, leaving their own stones in play can also be dangerous. Guards can be drawn around by the other team, and stones in the house can be tapped back (if they are in front of the tee line) or frozen onto (if they are behind the tee line). A frozen stone is difficult to remove, because it is "frozen" (in front of and touching) to the opponents stone. At this point, a team will opt for "peels", meaning that the stones 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 culture

The Fingask Curling Club, Perthshire, Scotland, in 1854
Competition teams are normally named after the Skip, e.g. Team Martin for skip Kevin Martin. Amateur league players can (and do) creatively name their teams, but when in competition (a bonspiel) the official team will have a standard name.
Top curling championships are typically played by all-male or all-female teams. The game is known as mixed curling when a team consists of two men and two women. The Canadian Mixed Curling Championship is the highest-level mixed curling competition, in the absence of world championship or Olympic mixed curling events.
Curling is played in many countries including Canada, United Kingdom (especially Scotland), the United States, 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 Scotties 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 (ranked 5th of 10 Canadian provinces), Manitoban teams 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[neutrality is disputed] curlers. Ernie Richardson and his family team dominated Canadian and international curling during the late 1950s and early 1960s and are generally considered 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.

An amateur sport
While Canadian bonspiels (tournaments) offer cash prizes, there are no full-time professional curlers. However, some curlers make a considerable portion of their income from curling. Some stay-at-home mothers or house-wives can claim curling as their profession. Still, curling survives as a people's sport, returning to the Winter Olympics in 1998 with men's and women's tournaments after not having been on the official Olympic program since 1924 (that year's curling competition, for men only, was confirmed as official by the IOC in 2006). Because accuracy, strategy, skill, and experience are more valuable in curling than traditional sports virtues of speed, stamina, and strength, most competitive curlers are older than their counterparts in other sports. However, there are many young teams who turn heads, and junior curling is quite popular, with national finals being televised nationwide in Canada.

Good sportsmanship
More so than in many team sports, good sportsmanship is an integral part of curling. For example, celebrating an error by the opposing team, fully acceptable in some sports, is frowned upon in curling. Even at the highest levels of play, players are expected to "call their own fouls", so to speak, such as alerting the opposing skip if they "burned" a stone. It is also traditional for the winning team to buy the losing team a drink after the game. (This is an interesting contrast to the game of darts, where the loser traditionally buys the winner a drink by way of congratulations.) This is often referred to as the Spirit of Curling.
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 honourable act and does not carry the stigma associated with quitting, and allows for more socializing. To concede a match, members of the losing team remove 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.

Additional information
The means of preparation one must take to be competitive in the sport of curling go beyond physical fitness and above-average agility. The competitor must not only be able to have an extensive understanding of classical mechanics with an emphasis on friction, but must be able to apply this knowledge to the playing field. This is a commonly overlooked fact. Curling is an excellent example of the adage "easy to learn, but difficult to master".

By the numbers
The participants and commentators of curling use various measures to relate information about the behaviour of ice and the individual rocks thrown. The ice in the game may be fast or slow. If the ice is fast, a rock will travel farther with a given amount of weight on it. The speed of the ice is measured in seconds. One such measure known as "hog-to-tee" is the amount of time that a rock will take from the moment that it crosses the hog line at the throwing end to come to rest at the tee line at the playing end. If the ice is slow, the rock will have to have more weight in order to reach the tee line and would reach the tee line more quickly. Increasing the weight of the rock will increase the momentum of the rock. Thus, the speed of the ice (in seconds) is lower if the ice is slow than if the ice is fast, in which case the rock would have to be thrown more slowly and would take longer to get there. The time is longer because the stone takes longer to slow down the keener the ice.
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.