Hockey is a sport played on ice by players wearing skates. The skates have sharp metal blades that allow the player to glide across the ice. Players are equipped with a hockey stick which they use to propel a rubber disc, or puck, along the ice surface. The players must advance the puck into their opponents goal to score. The team with the highest score wins the game. The opposing team defends their goal in order to prevent the scoring of goals. While hockey can be played on virtually any ice surface by amateur players, the game has evolved into a spectator sport with fairly standardized playing surfaces. Professional hockey is played on a large ice surface, called a rink, that is roughly rectangular. In order to assist the movement of the puck, the corners of the rink are rounded. This allows a puck to enter the corner and continue traveling towards the center of the rink. A goal is positioned at each end of the rink. Each team defends one of the goals. While players attempt to score goals, their opponents attempt to stop them. If a player stops the advancing of the puck, he may attempt to advance it in the other direction towards his opponent's goal. Of course, his opponents will attempt to stop him. The game progresses in a back and forth fashion while a clock counts down the duration of play. When the regulated time has expired, the game is over. Depending on the circumstances of the game, a tie in the number of goals may be allowed at the end of the game or the teams may continue to play. This "overtime" session is designed to allow one of the teams to score a goal which would terminate the game with an established winner. The game of hockey can be quite dangerous so precautions have been made to protect players and spectators. Modern hockey rinks have walls to contain the puck within the playing area. Many facilities extend netting above the walls to stop pucks that have been accidentally shot with the hockey stick towards the spectators. Players wear helmets and pads to reduce the chance of injury from puck contact. Despite the precautions, there can be injuries to spectators or players. Everyone at a hockey game is advised to monitor the movement of the puck very closely as it may be deflected towards a person at very high speed.

Hockey Leagues
There are many separate hockey organizations, called leagues, around the world. The leagues organize teams of players and schedule games between teams. Leagues are either amateur or professional. Many amateur players hope to build their skills in order to eventually qualify for a professional position. The pinnacle of professional hockey is the National Hockey League which is comprised of 30 teams in the United States and Canada. This league attracts many of the best players in the world who become top ranked stars for their play. Countries such as Sweden, Finland, Russia, Czech Republic, German, Canada, the United States, and more, have provided citizens who have made impressive showings in the National Hockey League. Most leagues have the teams play during a regular season and then a playoff to decide the overall champion. The National Hockey League teams playoff for the championship. The winning team is awarded the Stanley Cup, which is one of the oldest prizes in team sports. It was established in 1892 by then Governor General of Canada the Lord Stanley of Preston. The Stanley Cup is regarded as the highest award a hockey team can attain. Players on the winning team have their names inscribed on the Stanley Cup. The trophy is held by the winning team until the subsequent year's champion is determined. The other notable championships includes the World Cup of Hockey and the Winter Olympics where teams from various countries play for the top position.

Hockey Players
Hockey is a game which requires particular skill to be played well. At the top of the hockey establishment, hockey players are professionals who play the game for a yearly salary. The highest skilled players command salaries in the millions of dollars. Because of the difficulty involved in skating well, handling the puck deftly with a hockey stick and scoring goals while opponents attempt to stop them, good hockey players are rare. The required skills are usually developed over many years through instruction and practice. Regardless of the effort expended, many players are never capable of advancing to a skill level necessary to play professional hockey.

Hockey Positions
Hockey players are organized into various positions on a team. At the goal, the "Goalie" represents the last defense for a team. The goalie will use his equipment to catch, deflect or shot the puck away from the goal. Since the opposing players can propel the puck toward the goalie at great speed, most goalies are given extensive protection. They will often wear pads to cover most of their body. These are designed to absorb the force of impact should the puck strike the goalie's body. Goalies are generally confined to their end of the ice rink, but they can occasionally venture outwards.
Two defensemen play in front of the goalie. They are mobile skaters that attempt to stop advancing opponents. Defensemen are also vulnerable to impacts from the puck so they typically wear significant padding as well. They usually play in a position quite near their goalie, but they are not obligated to. It is fairly common for a defenseman to take the puck to the opposite end of the rink and attempt to score himself.
Two wingers play in front of the defensemen, one on each side of the rink, although they are not restricted to a set area.
They flank the Center player which is often the lead for offensive moves into the opponent's end of the rink. During the course of play, the wingers and center will roam about the ice surface. They will assist the defensemen in clearing the puck from their end of the rink and advance it to the other. They are generally concerned with scoring goals but they do attempt to block opposing goals whenever possible.

Referee and Linesmen
Modern hockey is played with a set of rules that are administered by a referee. The referee is outfitted with skates as well. He roams the playing surface watching for rule infractions by any of the players, intentional or accidental. The referee assesses penalties for such infractions. These range from having a team play without the offending player for two or more minutes to complete ejection of the player from the game. The referee must watch for infractions that are increase danger to the players or result in an unfair advantage to a team. Should a player trip, unfairly impede, injure, or otherwise affect an opposing player during the play, a penalty is assessed. Such infractions, however, must be witnessed by the referee. In many hockey organizations, there are two referees who administer each game. These may be assisted by one or two linesmen. The linesmen judge less serious infractions such as advancing into an opponent's territory prior to the travel of the puck. Some hockey leagues allow the linesmen to advise the referee on serious infractions such as striking a player with a hockey stick with excessive force. This results in a penalty for the infraction and is designed to reduce the chance that a player is able to escape punishment for undesirable actions. Linesmen also allow the resumption of play after a stoppage. They assemble the players on opposite sides of a faceoff circle. This is a painted spot on the surface of the ice. The linesman drops the puck in the circle which signals that the two players facing off can attempt to gain possession of the puck. They they resume the objective of scoring into the opposing team's goal.

Video Replay
The National Hockey League uses a video replay to determine the validity of scored goals. In many cases, there can be considerable doubt about whether a goal was legally scored or invalidated due to an infraction of a rule. Video cameras are positioned to view each hockey goal from several angles. In the event of a goal scoring question, league officials review the camera recordings to make a determination about the goal. Play is stopped while the video is reviewed. When a ruling for or against a goal is made, the game referee announces the result. If a goal was scored, the fact is recorded. If not, play resumes from a faceoff.

Hockey is a popular spectator sport. Many of the games attract thousands of paying fans to the hockey arenas where they watch the game live. The highest attendance figure for a live hockey game was over 71 thousand. Millions more often watch hockey games that are broadcast on television. While the highest number of viewers are for championship games, especially the final playoff series in the National Hockey League, regular season games often have 10,000 to 17,000 or more spectators in the arena and high numbers of television viewers. While hockey has the smallest fan base of the four major professional sports, in Canada it is very popular, outranking the other three sports in that country. Since it is a winter sport played on ice, the hockey season is usually in the northern winter. Due to the number of games, the final championship games, especially in the National Hockey League can occur in the early summer.