Curling University

Millions of people watch Curling during the Olympics but still don't really understand what they are watching....or how complex a game it really is.

We have designed a curling primer we call Curling University.  Read through and memorize the details of the 100 level courses and you will enjoy watching the game more and be the curling expert among your friends.  Read through and memorize the details of the 200 and 300 level courses and you will understand the complexity of the game and know more than some of our club members.

100 Level Courses - Designed for the Curling Spectator

Curling 101 - The Basics

Curling is an Olympic sport in which two teams of 4 players each (in traditional Curling) take turns sliding granite stones down a 150 ft. sheet of ice to a set of rings with the goal of having your stones closer to the center of the rings than your opponent's stones, once all the stones are thrown. 

• The Positions - Each team consists of 4 players:
  • "Lead" - Throws the first two stones for their team and sweeps when they are not the one delivering the stone
  • "Second" - Throws the third and fourth stones for their team and sweeps when they are not the one delivering the stone
  • "Third" (or "Vice-Skip" or "Vice") - Throws the fifth and sixth stones for their team, sweeps when the Lead and Second are throwing and replaces the Skip when the Skip is throwing
  • "Skip" - Is the captain of the team and calls the strategy of the game.  They traditionally throw the seventh and eighth stones for their team (although some teams have their skips throw earlier in the end) and direct play in the far house when they are not the one delivering the stones.
• "End" - Each end (similar to an inning in baseball) consists of all 16 stones being thrown (8 for each team, alternating with the opponent), and the score is determined.
• Scoring - Only one team scores in each end and that is the team whose rock is closest to "the pin" (the pinhole at the center of "the button".  The button is the circle at the center of the rings).  This team will score one point for each stone closer to the pin than the opponents closest stone.  Stone must be on or overhanging the rings to potentially score a point.  If neither team has a stone on the rings, it is a "blank end" and neither team scores. 
• "The Hammer" - The team that throws last has what is known as the hammer which is an advantage.  At the club level, the team that starts with the hammer is determined by a coin toss (or rock-paper-scissors during COVID) and, at the elite level, the team that starts with the hammer is determined through a last stone draw in which each team throws a single stone and the distance from the pinhole at the center of the button  is measured.  The team closest to the pinhole gets hammer.  After the first end, the team that does not score gets the hammer.  In the event of a blank end, the hammer stays with the team who had the hammer in the previous end.    
• The different curling shots:
  • Guard - A shot designed to come to rest on its own between the hog line and the house.  To be used to protect an existing rock or provide protection for a rock that will be thrown later
  • Draw - A shot designed to come to rest on its own on the house.  
  • Takeout - A shot designed to knock another stone out of play.  
• Burned Rocks - If a player touches a rock in motion with their broom, their body or any other object, they have burned the rock and it comes out of play.
• Weight - In the sport of Curling, the term "weight" refers to the velocity of a stone
• Line - In the sport of Curling, the term "Line" refers to the direction of the stone

Curling 102 - Curling Ice

Curling ice is not like hockey ice.  Curling ice is designed to be absolutely level but not flat.  The ice is "pebbled" by sprinkling water over the ice which causes slight bumps on the ice.  These bumps (or pebble) reduce the friction enough for the stones to slide down the ice and also produce the characteristic curl that gives the sport its name.  Good curling ice is pebbled and scraped for multiple days (with the scrape just scraping a portion of the pebble off) which creates a spanish lace type of effect.

The most common question asked about Curling ice is whether a Zamboni is used like you see at a hockey rink  The answer to that is no.  Zamboni's are imprecise instruments with a slightly curved blade.  Curling requires the ice to be extremely level.  So instead of a Zamboni, we use what is known as an ice scraper.  They are generally battery operated walk-behind units that have a very sharp and very flat blade.

Pebbled ice with a spanish lace effect	An Ice Scraper

Ice Scraper

Pebble is applied to the ice by the icemaker using a modified backpack sprayer (like you might use to put down a lot of weed killer) that is purely gravity fed and holes of a certain size on a "pebble head" inplace of a sprayer.  The icemaker walks backwards down the ice waving his arm back and forth to get a regular distribution of the pebble.  Once the pebble is applied to the ice, it freezes nearly immediately.  The icemaker will then run a "nipper" over the ice.  The nipper shaves the very top of the pebble off to increase the speed of the ice at the outset of the game.

Ice being pebbled	A Pebble Head	A Nipper

Curling 103 - Curling Stones

A curling stone is of circular shape, having a circumference no greater than 36 in., a height no less than 4.5 in., and a weight, including handle and bolt, no greater than 44 lbs. and no less than 38 lbs.

200 Level Courses - Designed for the Novice Curler

Curling 201 - The Basics

Curlers deliver the stone by pushing off from the hack (similar to a starter's block in track) with their dominant leg with a teflon slider under their non-dominant leg.  They then release the stone with a pre-determined rotation which causes the stone to curl in the direction of the rotation as they decelerate.  2 other team members will sweep the stone to make the stone go further and/or to slightly impact the direction of the stone (more details in Curling 301).  Curlers must release the stone before the hog line (the thick line located 27 feet from the hacks) and the stone must fully pass the far hog line to stay in play.  Once an opponent's stone touches the tee line that bisects the rings (or "the house") at the far end of the ice, the other team's skip can sweep the stone to try to get it deeper in, or potentionally through, the house.

Types of Guards:

• High Guard - A guard designed to come to rest in the first third of the guard zone (the area between the hog line and the house)
• Mid Guard - A guard designed to come to rest in the middle third of the guard zone 
• Tight Guard - A guard designed to come to rest in teh last third of the guard zone (closest to the house)

Types of Draw Shots:

• Open Draw - A draw shot designed to come to rest in the open
• Come Around - A draw shot designed to come to rest behind another stone
• Freeze - A draw shot designed to come to rest against or very close to another stone.  Freezing a stone to an opponent's stone generally protects your stone because your opponent cannot remove your stone without losing their own stone and it often will take two shots to remove a frozen stone.

Types of Takeouts:

• Nose takeout - A takeout designed to hit another stone in the center of the rock ("the nose") which will transfer 100% of the energy to the hit stone and the thrown stone will stop dead
• Hit and roll - A takeout designed to hit another stone to the left or right of the nose.  The hit stone will still generally leave the rings but some of the force will be retained by the thrown stone which will then roll left or right
• Tap - A takeout designed not to remove a stone from play but instead just move a stone further back in the rings
• Peel - A shot designed to remove both the target stone and the thrown stone from play.  Peels are generally thrown with a lot of velocity and hit just the left or right third of the target stone

Curling 202 - Curling Ice 

The ice at a particular facility will change day to day and will even change during the course of a game.  Factors that impact the ice include the surface temperature of the ice, the amount and quality of the pebble, the humidity and more.  During the course of the game, the speed of the ice will vary.  Most commonly, the ice will be a little slower at the start of the game.  As the game progresses and stones go down certain paths, the stones will erode the pebble a bit and the ice will speed up on those paths.  Eventually, commonly used path will have the pebble worn down enough that the ice will slow down again.  "Reading the ice" is an important skill that is 

Curling 203 - Curling Stones

300 Level Courses - Designed for the Club Curler

Curling 301 - The Basics

The Five Rock Rule - The Five Rock Rule is a rule that was introduced in the 1991-1992 season as the 4 rock rule and then updated to the 5 rock rule in the 2018.  Under the 5 rock rule, a team cannot knock its opponent's guards out of play until the 6th rock in the end is played.  A team can knock their opponent's stone elsewhere in play or can remove their own guards, but if they knock an opponent's guard out of play with one of the first 5 rocks, the thrown rock is removed from play and all other stones are returned to their previous position.  This rule was introduced to encourage scoring as it gives teams an opportunity to hide stones behind their guards.  Due to this rule, the team's leads are often asked to place guards with their stones.  Teams without the hammer will keep their guards in the center third of the sheet ("a center guard") to block the path to the button.  Teams with the hammer will typically place their guards in the outside thirds of the sheet ("corner guards")

Teams with the Hammer are generally expected to score two points.  If they only score one point ("a force"), it is considered a victory for the team without hammer.  If the team will hammer gives up one or more points, it is considered "a steal".  Oftentimes, especially at the professional level, teams with the hammer will seek to blank the end (an end in which nobody scores by nobody having a stone on the rings) so that they can have the hammer again in the next end.

Directional Sweeping - In 2015, a new broom was brought to market by Hardline.  This broom had a slightly different material that was a bit more abrasive than prior brooms.  Team Gushue from Newfoundland & Labrador discovered that with this more abrasive fabric they could actually "steer" a rock in the opposite direction of the rotation by having just the sweeper on the outside of the curl sweep.  This created a lot of controversy and became known as Broomgate.  This new fabric and other fabrics introduced by other broom manufacturers were banned.  Additionally, the old style horse or hog's hair brooms were also banned.At the elite level or in any event that leads to a National championship, only a certain type of fabric can be used.  These legal brooms have a distinctive yellow color on their broomhead.  However, since this time the concept of directional sweeping has been adopted.  Under directional sweeping, teams use just a single sweeper to impact direction of the stone and both sweepers to impact the distance of a stone.  To impact the direction of a stone, teams will have the player on the inside of the curl sweep to reduce the amount of curl and the player on the outside of the curl sweep to enhance the amount of curl.  While directional sweeping does have an impact it is dramatically less of an impact that Team Gushue demonstrated at the start of Broomgate. 

Weights

• The Randy Ferbey Team, a top level Canadian curling team in the early 2000s, developed a communication mechanism for weights using the numbers 1-10.  You will hear some teams state the weight as a number when calling the shot or when sweeping (for the sweepers to communicate to the skip what they believe the weight to be).  The numbers correspond to weights as follows:
  1. High Guard
  2. Mid Guard
  3. Tight Guard
  4. Top 12 Foot Circle
  5. Top 8 Foot Circle
  6. Top 4 Foot Circle
  7. Tee Line
  8. Back 4 Foot Circle
  9. Back 8 Foot Circle
  10. Back 12 Foot Circle
• Beyond the 1-10 of the Ferbey method, the following additional weights are used commonly (in order of increasing weight):
  • Hack Weight - A shot that would come to rest at the hack
  • Board Weight - A shot that would come to rest at the board 
  • Bumper Weight - A shot that would hit the board and bounce back slightly 
  • Control Weight - A downweight takeout
  • Normal Weight - A normal weight takeout
  • Firm Weight - An Upweight takeout
  • Peel Weight - Maximum weight, designed to be able to knock a stone out and roll the shooter out as long as it doesn't hit the target stone directly on the nose

Hog Line - There is one exception to the hog line rule that requires a thrown stone to fully pass the hog line to remain in play.  If a thrown stone makes contact with a stone that is already fully across the hog line but, in doing so, stops on or before the hog line, the thrown stone remains in play.

Burned Rocks - While in-motion rocks touched by a player are burned, there are some specific practices in how this is handled:

• If the rock is burned between the hog lines (or inside the near hog line), the stone is immediately removed from play
• If the rock is burned after crossing the far hog line, the offending player should call out loudly that they burned the rock but let the rocks all come to a stop.  The non-offending team then gets to decide if they want to:
  • Let the rocks stay as they came to rest,
  • Remove the burned rock and place the rocks back to where they were previously, - OR - 
  • Position the rocks how they would have ended up had the rock not been burned

 Basic Curling Strategy - Here are some basics of curling strategy:

• When a team is ahead - When a team is ahead by more than a couple of points, their goal becomes to ensure that their opponent scores no  more than one point when they have hammer.  To do this, a common strategy is to play in the house, meaning not putting down a guard but throwing onto the top 8 foot circle, perhaps.  The team that is behind will need to ignore the stones on the house until later in the end if they want to score more than one.  
• When a team is behind - When a team is behind by more than a couple of points, the best strategy is generally to either get guards down or freeze to stones in the rings
• When a team is significantly ahead near the end of the game

Curling 302 - Curling Ice

Curling 303 - Curling Stones

Curling stones are made from special types of microgranite mined in two places in the world.  Common Green Ailsite and Blue Hone Ailsite are forms of granite mined from Ailsa Craig, a small island located in the Firth of Clyde.  Pink, Blue or Green Trefor microgranite comes from Trefor, Wales.  The microgranite used in curling stones is granite that fomed more quickly than most traditional granite and is therefore impermeable to water.  

There are three main parts of a curling stone: (1) the handle, (2) the striking band and (3) the running surface.

The handle of a modern curling stone can be either plastic or metal.  Most curling clubs will have the traditional plastic curling handle known as a "Curlex" handle.  Curling handles used at some competitive events are metal handles and have sensors in them that detect heat on the handle and the hog line.  These handles will turn on a green light if the handle does not sense a hand on the handle when the stone hits the hog line and will turn on a red light if the handle does detect a hand when the stone hits the hog line.  Handles are attached to the stone with a bolt that runs through the center of the curling stone.  Curling stones will typically have 3 identifiers on the top.  The first letter or number is located at 12 o'clock on the dial and indicates the sheet to which the stone belongs.  Sheets are typically identified by number (1-4 for a 4 sheet club) or letter (A-D for a 4 sheet club).  The numbers at 3 o'clock and 9 o'clock on the stones will be identical and indicate the stone number (1-8).  Typically, curling stones are thrown in numerical order (1-8) nut top level curlers can recognize the difference in behavior between curling stones and may adjust the order that stones are thrown.  Curling handles will be of two colors (one for each team).  The most common curling handle colors are red and yellow, but a wide variety of handle colors are in use throughout the world.

The striking band of a curling stone is the portion of the curling stone that comes into contact with another curling stone when they collide.  Blue Hone Ailsite is the best microgranite for the striking band of curling stones as it the strongest and least likely to break down due to the repeated contact.