Curling 101

The Very Basics
The Curling Rink
The Curling Stone
Delivery of the Stone
The Game
The Team
The Ice
Sweeping
Summary

The Basics

Curling is played within a curling rink on a playing surface ice called a 'sheet' with granite stones. The goal of the game is, after all 16 stones are played (8 by each team), to have a stone of your team's closest to the center of the house, called the 'tee' (see rink below). This is accomplished by sending your stone to rest in scoring position by utilizing one of many shots. Some for these are (a 'draw'), by knocking your opponent's stones out of scoring position (a 'takeout'), and by guarding your own stones with others. The team with the closest stone to the 'tee', inside the house, scores a point, or more if they also have the second closest stone and so on. Each round is called an 'end' and consists of two stones delivered by each player on each four-player team. The stones are delivered from the hack on one side of the sheet to the house on the opposite side. This consists of the player pushing off from the hack with the stone and releasing it with a spin, or 'curl'.

The Curling Rink

The playing surface played on in a game of curling is ice. The ice playing surface is called a 'sheet' and is within a 'curling rink'. The 'sheet' is 138 feet long by approximately 14 feet wide. The main features of the sheet are the 'House', the 'Hack', the 'Hog Line' and the 'Tee Line'. The 'Hack' is where one delivers or throws the stone. The 'Hog Line' is the line that one must release the stone before during delivery of the stone, and the line at the other end of the ice that ones stone must pass to be considered in play. The scoring area - the 'House' - consists of three concentric rings, 4, 8, and 12 feet in diameter The small circle at the center of the house is called the button, and the center of the button is the tee. The distinct areas are marked underneath the ice surface by using either paint or ribbon.

The Curling Stone

The curling stone originated in Scotland from large chunks of rock bowled across the ice, none having any particular size or shape. They evolved into what are now matched sets of fairly uniformly made stones. They are all made of pure granite, and they are amazingly hard. The best stones come from a single granite mine on an island off the coast of Scotland. Shipping is quite expensive due to weight (16 stones in a set at 42 pounds a piece, not including packaging), and manufacturing is expensive because of the toughness of the material, which is ground with diamonds. Hence, the sets of curling stones are owned by the club and not by individuals.

The stone is concave on both the upper and lower surfaces. On some stones, the degree of concavity is different on both sides to allow for reversing the stone for 'faster' or 'slower' ice. A handle, usually on a circular plastic disc, is bolted onto the stone through a channel running through the middle of the stone to a bolt on the other end, as shown in the red highlighted region in the cross-sectional diagram. The figure on the right shows the top of the stone, more obviously concave, but without a smooth running surface. The handle is affixed onto this circular surface.

In the figure above, part A is the bottom of a curling stone, which is concave, although you can't see it well in this picture. The red circle is the actual running surface of the stone. This allows the stone to go farther, more accurately, and pick up more 'curl' than would be possible on a flat surface.

There is a lighter-colored band in a ribbon around the curling stone. This is the 'striking surface'. In manufacturing, the entire stone if very highly polished. This surface is dulled down for the purpose of improving collisions with other stones, both so that there will be a larger contact patch in the collision and so that the stones will not chip.

Delivery of the Stone

	The stone is delivered sort of similarly to a bowling motion. Actually, it's not that similar, but it's the only thing that even resembles it (see example of delivery below). You start off at what's called a 'hack', or basically a block sticking out of the ice.
	Your first motion is to take the stone and pull it backwards to just in front of the hack in the backswing, then you push it forward into a smooth glide down the ice. The broom is used as a support during delivery. You slide on your lead foot, with you other foot and leg stretched out behind you, dragging.
	However, to deliver a stone well, you should glide along with the stone as far as possible.
	Good curlers usually glide very close to the ice, in an odd, very stretched pose.
	You must release the stone by the 'hog line' (see the curling rink for location of the hog line). As you slow down, the stone glides on, to come into play on the opposite side, beyond the other hog line.

Example of Curling Stone Delivery...

The Game

Curling is a social game, that is full of strategy. Although it is often described as 'chess on ice' for its strategy, it more closely resembles bocce or shuffleboard.

The object of the game is to get closest to a target area and maintain that advantage while your competitor tries to get closer or knock you out. The strategy comes into play with planning shots like 'guards', 'takeouts', and 'draws' and ability to control the speed and direction of each shot. The matches are as social or competitive as desired depending on the curlers skill level and the nature of the match.

A great deal of effort goes into planning an end so your team's stone ends up closest to the Tee. There are a number of different strategic moves, and here we show the standards:

	The Draw A 'Draw' is obviously the most basic move. You send the stone down the sheet, and with the help of the sweepers and the direction of the skip, you somehow get the stone to stop where you want it. Here is shown a perfect draw into the Tee, the center of the House. This would be fairly pointless as a first shot, as it could easily be taken out.
	The Takeout Here, the green stone is taken out by the yellow. The yellow continues on, maintaining most of its momentum (usually takeouts are thrown harder than draws), while also knocking the green stone out of play. The yellow stone could, of course, remain in play if it remained in bounds, but in a basic takeout, the only concern is removing the other team's stone.
	The Guard Guarding is, as its name implies, placing a stone in front of another (with a draw) to prevent a takeout. In this diagram, we see two green stones and three yellow stones that have already been played. To protect stone A, the yellow team has sent a draw, stone B, immediately in front of A. This prevents a takeout by stone C as would have happened here.

The Team

The team consists of four players, called the 'Skip' the 'Lead', the 'Second', and the 'Vice'. The Skip is essentially the team captain -- generally the most experienced, well-tempered person on the team. Play rotates so that all four team members get to deliver two stones each. At any time, there is one skip, two sweepers, and one person delivering a stone. When the Skip is scheduled to deliver his stones, the 'vice' (also called the 'third' so called because he is the third in line to deliver stones) acts temporarily as skip. From this, we can pretty much guess that the later stones are more important to the outcome of the game. Sweeping is directed by the skip, and the type of shot, as well as the placement of the shot, is called by the skip.

The Ice

A large element of the game not mentioned so far is the 'curl' of the stone. As you can see in the above diagrams, the stone is not coming in on a perfectly straight path. This is due to the curl put on the stone by the curler. As the stone is delivered, a slight spin is put on it, acting like a very, very slow curveball.

The pebble is what helps the stone pick up the lateral motion. As is seen here, the ice is sprinkled before the game with a 'pebbler', which creates a smooth hilly effect on the ice, much like little pebbles. Without the pebble, the stone would not be able to travel as far. Therefore, the small travelling surface of the stone itself combined with the small contact area of the ice (created by the pebble) allows the rock to travel further than on flat smooth ice. Sweeping also aids in increasing the travel distance of the stone.

Sweeping

Either a curling brush or broom is used to sweep in the game. Sweeping fine tunes the shots, and sweeping is what makes curling truly a team sport.

Sweeping affects the ice in front of the moving stone in three ways:

Smoothing or polishing the pebble,
Removing frost or debris,
Momentarily warming the ice to create a thin film of water under the stone that acts as a lubricant.

As a result, a swept stone will lose its momentum more slowly and thus travel further. For draw shots, good sweepers will sweep just enough to bring the stone to its desired position. On takeouts, sweeping will hold a stone on the line of delivery longer and reduce the amount of curl.

Summary

Each player shoots or delivers two stones each end, alternately with their counterpart on the opposing team. A twist of the handle on release makes the stone curl, a little like in bowling.

All four team members shoot two stones an end and sweep for their teammates' shots. While one player shoots, two sweep as needed. Sweeping polishes the ice so the stone travels farther if delivered too softly, and vigorous sweeping requires fitness. In a typical two hour game, a curler walks almost two miles.

The skip acts as team captain and strategist. Strategy is a major factor in curling, as important as shooting skill. Some people call curling "chess on ice".

The playing surface is called "a sheet of ice", and is designed to allow play in both directions.

The object of shooting is to get the stone, or rock, to come to rest at a predetermeined place (a draw or guard) or to move another rock (a takeout or raise).

The score is determined after each end of 16 stones. A 12 foot circle, the house, is the scoring area. Stones in the house must be closer to the tee (center) than any opposing stone to score.

The maximum score in one end is eight points. Typically, one to three points are scored. Games are 8 or 10 ends, lasting 2 to 2.5 hours.