What is polo?

Two teams of four riders. A small hard ball. Mallets, a grass field the size of nine football pitches, and horses doing 50 km/h while their riders lean out of the saddle to hit a moving target. That's polo — the ancient cavalry game that became “the sport of kings.”

The shape of a match

• A match is divided into periods called chukkas (or chukkers), each about 7 minutes of play. Matches run from 4 chukkas at club level up to 6–8 in high-goal polo.
• Teams score by hitting the ball between the goalposts at either end — from any height, at any speed. After each goal, teams swap ends, sharing out wind and ground advantages.
• Riders change horses between chukkas (and often mid-chukka) — the pace is simply too fast for one horse to sustain. A serious player's string of ponies is their most important equipment. More.
• Mounted umpires (usually two) referee, with a referee on the sidelines as tie-breaker.

The one rule that explains everything

Nearly all of polo's rules protect one concept: the line of the ball. The ball's travel creates an invisible line, and the player following that line on its natural side has right of way — like an unmarked road with strict traffic law. Opponents may ride a player off shoulder-to-shoulder or hook their mallet, but crossing the line dangerously in front of someone at speed is the game's cardinal foul. It looks chaotic; it's actually traffic law at full gallop. The rules in detail.

Why it grips people

Polo is the rare sport where a team athlete is half of a two-species partnership. The riding alone is elite sport; add ball-striking, tactics and physics-heavy defending and you get what devotees claim without blushing: the most demanding team game on earth — and one of the most beautiful to watch from a picnic blanket. Go watch one.