structural:scholar_edition, structural:summarization
Polo or Chovgan (Persian: چوگان) is a ball game that is played on horseback, a traditional field sport and one of the world's oldest known team sports. It originated in ancient Persia (modern-day Iran), dating back over 2,000 years. Initially played by Persian nobility as a training exercise for cavalry units, polo eventually spread to other parts of the world. The game is played by two opposing teams with the objective of scoring using a long-handled wooden mallet to hit a small hard ball through the opposing team's goal. Each team has four mounted riders, and the game usually lasts one to two hours, divided into periods called chukkas or chukkers.

Polo has been called "the sport of kings", and has become a spectator sport for equestrians and high society, often supported by sponsorship. The progenitor of polo and its variants existed from the 6th century BC to the 1st century AD, as an equestrian game played by the Iranian. In Persia, where the sport evolved and developed, it was at first a training game for cavalry units, usually the royal guard or other elite troops. It is now popular around the world, with well over 100 member countries in the Federation of International Polo, played professionally in 16 countries, and was an Olympic sport from 1900 to 1936.

Arena polo is an indoor or semi-outdoor variant with similar rules, and is played with three riders per team. The playing field is smaller, enclosed and usually of compacted sand or fine aggregate, and often indoors. Arena polo has more maneuvering due to space limitations, and uses an air-inflated ball slightly larger than the hard solid ball used in field polo. Standard mallets are used, though slightly larger-head arena mallets are an option.