Each team skates, or uses, no more than six players at a time, usually one center, two forwards, two defensemen, and one goaltender, or goalie. Goaltenders are allowed heavier and wider sticks and wear additional protective equipment, including face masks. Ice hockey skates differ from those used for other kinds of ice skating. The blade is thinner and shorter, with a plain, pointed end, and the boot is lower and thicker. Play begins with a face-off, when the referee drops the puck between the opposing centers.
Teams attempt to score through a combination of passing and shooting the puck with their sticks.
If a player precedes the puck into the attacking zone, the play is ruled offside, and a face-off is held near the spot where the misplay occurred. Substitutions of players are frequent during play. The game is divided into three 20-minute periods, with a change of goals at the end of each. Under international rules, if the score is tied after three periods, a 10-minute overtime is played, during which the game ends immediately after a goal is scored. If the game is tied after the overtime period, it ends in a tie.