The outdoor game, which Americans refer to as field hockey, is similar in tactics to both football and its namesake on ice.
China could not get past Australia in the last Olympic final
Hockey is an 11-a-side game played over two halves of 35 minutes, with goals more often than not coming from set-pieces such as corners or penalties.
The Olympic tournament includes 12 men's teams and 10 women's teams, split into two pools of six and five teams respectively.
For the men, each team plays each side in its pool once, with the top two in each group advancing to the semi-finals, while the others play a classification round to determine their final placing.
The semi-final winners go through to contest the gold and silver medals, while the losers play off for the bronze.
The top three in the women's pools advance into another pool of six.
Group A: Egypt, Germany, GB, Pakistan, S Korea & Spain
Group B: Argentina, Australia, India, Netherlands, N Zealand & S Africa
Group A: Argentina, China, Japan, N Zealand & Spain
Group B: Australia, Germany, S Korea, Netherlands & S
These teams play each other once with the top two at the end contesting the gold. The teams ranked third and fourth play for bronze.
On the field, only the goalkeeper is allowed to use their hands, while all other players must make contact with the ball using hockey sticks.
Touching the ball with any other part of the body yields a foul and players must only use the flat face of the stick; it is illegal to use the rounded side.
Goals during the normal run of play can only be scored from within the scoring circle, which arcs 16 yards in front of goal.
If a defender hits the ball unintentionally over their back-line then a long corner is awarded to the attacking team.
The ball is placed on a spot five metres in from the corner flag and the attacking side hits it back into play and attempts to score.
However, should the ball be hit intentionally over the back-line then a penalty corner is awarded against the defending side.
The ball is placed nine metres from the nearest goalpost and the attacking side is allowed a free hit. The ball is usually struck inside to the edge of the goal circle, where one player will set up the shot for another to try to score.
DID YOU KNOW?
The name hockey is derived from the French word hoquet, which was the old word for a shepherd's crook
This provides some of the game's most spectacular moments.
Getting in the way of a rasping shot can result in serious injuries, though a shot from a penalty corner must not hit the net higher than the 18-inch backboard in the goal.
Players must also watch out for dangerous play. They cannot lift the sticks above their head, wield them in a dangerous manner or use body or stick to impede an opponent.