The modern indoor variant is called arena polo. In arena polo, there are 3 instead of four players on each team and chukkers (periods) are 6 1/2 minutes in length, in outdoor polo the chukkers are 7 1/2 minutes in length. The playing area is 300′ x 150′.

Another modern variant is snow polo, which is played either outdoor or indoor on snow on a frozen ground or ice. Each team generally consists of three players and also the equipment differs from the sport of polo. Other variants include elephant polo, bike polo and Segway polo. These sports are considered as separate sports because of the differences in the composition of teams, equipment, rules, game facilities etc.

History

A game of Central Asian origin, polo was first played in Persia (Iran) at dates given from the 6th century BC to the 1st century AD. Polo was at first a training game for cavalry units, usually the king's guard or other elite troops. To the warlike tribesmen, who played it with as many as 100 to a side, it was a miniature battle. In time polo became a Persian national sport played extensively by the nobility. Women as well as men played the game, as indicated by references to the queen and her ladies engaging King Khosrow II Parviz and his courtiers in the 6th century AD. Certainly Persian literature and art give us the richest accounts of polo in antiquity. Ferdowsi, the famed Iranian poet-historian, gives a number of accounts of royal polo tournaments in his 9th century epic, Shahnameh (the Epic of Kings). In the earliest account, Ferdowsi romanticizes an international match between Turanian force and the followers of Siyâvash, a legendary Persian prince from the earliest centuries of the Empire; the poet is eloquent in his praise of Siyâvash's skills on the polo field. Ferdowsi also tells of Emperor Shapur II of the Sassanid dynasty of the 4th century who learned to play polo when he was only seven years old.Naqsh-i Jahan Square in Isfahan is in fact a polo field which was built by king Abbas I in 17th century.

Valuable for training cavalry, the game was played from Constantinople to Japan by the Middle Ages. Known in the East as the Game of Kings. The name polo is said to have been derived from the Tibetan word "pulu", meaning ball.Sports and Games of the 18th and 19th Centuries by Robert Crego. page 25. Published 2003. Greenwood Press. Sports & Recreation. 296 pages ISBN 0313316104

The origins of the game in Manipur are traced to early precursors of Sagol Kangjei. This was one of three forms of hockey in Manipur, the other ones being field hockey (called Khong Kangjei) and wrestling-hockey (called Mukna Kangjei). Local rituals such as those connected to the Marjing, the Winged-Pony God of Polo and the creation-ritual episodes of the Lai Haraoba festival enacting the life of his son, Khori-Phaba, the polo-playing god of sports. These may indicate an origin prior to the historical records of Manipur, which go back to the 1st Century A.D.