Orange County Polo Club

The first is that polo is a tactical team sport with 3 players on each side.

Like all tactical team sports, each player fills a specific role and supporting the team effort on both offence and defense.
The objective of the game is for a team to score the most goals by hitting the ball at their goal on each side of the arena.
Like other high contact team sports such as Rugby or Football, defensive plays such as “riding off” and “hooking” are important defense tactics and can result in fouls which results in penalties.
The polo is played in an arena 100 yards long and 50 yards across

The second is "the line of the ball". This is the imaginary line the ball creates as it travels from point A to point B.

This "line" determines the strict rules about how players can approach and attack the ball and each other, ensuring that the players and horses, traveling at 20mph when at top speed, do not collide resulting in serious injury to either horse or rider.
When two players ride to the ball, both hoping to hit it, they must ride on either side of the "line" so that both will have access to the ball. They must remain on opposite sides of the line, thus minimizing the risk of collision.
The line remains set until the ball is struck by a player, changes direction, and then a new line is formed.
A player may cross the line only when it does not create a hazardous situation such as a collision with another rider. This may result in a foul and a penalty to the team.

Team members are numbered 1 to 3 with No 1 being the attacking or offensive player and No 3 being the back or defensive player.
In Arena polo, the pivotal player on the team is the No 3, as he/she must stem the opponent's offence, turn the play to the attack, and pass the ball to his No 2 and No 1 player, as they turn to press the penetration toward the other team’s goal.
The No 1 player concentrates on opportunities for scoring, but also has the defensive responsibility for the opposing No 3 player. The No 2 team member supports No 3 on the pivotal plays, turns quickly to follow the No 1 player on attack, and “marks” the opposing No 2 player.
These assignments are not rigid, and each player must be prepared to make any play that will benefit his team, temporarily changing position as the pattern indicates.

When a foul occurs the umpires can award anything from a free goal to a free hit from a distance determined by the severity of the foul.
Three umpires, two on horseback and one on the side of the field, oversee the game and enforce the rules. Infractions generally involve hazardous riding and dangerous use of the mallet. Umpires can be recognized by their shirts which have vertical black and white stripes.

The full game is 4 periods, but often in club chukka more are played to accommodate all players. They are 7 ½ minutes each in length. Each period is called a "chukka". Each player in high goal(top level professional) tournaments uses a fresh pony for each chukka because the game is played at a very fast pace, with the horses galloping much of the time. In club games, ponies may play 2 chukkas in a game.