The basics are elegantly simple. The game is played between two teams of four mounted men on a field that measures 300 by 160 yards (as big as nine football fields) with goalposts at either end. The object is to move a ball downfield and through the goal in six periods of play known as "chukkers." Each chukker is seven minutes long. There are no time-outs except for injuries, penalties, or unsafe situations. And no replacement of players is allowed except for injuries.

Each of the four players is given an area of responsibility designated by a jersey number that indicates that area. The forward is designated Number 1; the most defensive player is called Number 4, or the Back. (There is no goalie.) The mid-action players are designated Number 2 and Number 3, with the latter controlling the attack and coordinating the defense. He's usually the highest-rated player on the team and the de facto captain. This alignment is designed to be fluid, however, and to change quickly under game situations.

The players have assignments on defense as well as a zone to play on offense. That is, they each have a man to cover when the action shifts, as it often does, countless times in a chukker. Strict limitations on what is and is not allowed in ball-handling and riding are meant to inject a degree of safety into what is inherently a dangerous game. Control of the game rests in the hands of the two mounted umpires and a third man, the referee, stationed at midfield.

The rules are based on something known as the "line of the ball." Each time the ball is moved, a line of travel is created that extends forward and backward from the ball. Players use that line to plan their approach to the ball, keeping it on their right (or off) side, where they have the right-of-way. Crossing the line close to an oncoming player who has the right-of-way may be dramatic, but it's often dangerous and thus is a foul. Cutting that line as close as possible is common in high-goal polo.

A swing at the ball can be blocked by a hook from another player's mallet or interfered with indirectly by a ride-off. Distantly related to a block in football, but with the added emphasis of a ton of horse and player, a ride-off is more like a body check in hockey - every bit as hard, fast, and effective.

As a spectator, you do have one responsibility during the intermission (halftime) that comes between the second and third chukkers: divot stomping! Fans surrounding the polo field are asked to make their way out onto the field to search out the clumps of grass that have been unearthed by the quick stops and starts of the ponies and then toe these clumps, known as divots, back into the ground, grass side up, of course. Don't forget to take part in this tradition of polo; it's a great chance to stretch your legs, meet other polo aficionados, and be a real part of the game.

Finally, be ready to set all the explanations aside and see the game for what it is: a feat for the senses, a glimpse into an endeavor that honors the disappearing virtues of daring, risk, danger, and action. It's polo, the ultimate sport!