THE LINE OF THE BALL

The most basic concept in the sport of polo is the line of the ball, a right of way established by the path of a traveling ball.
When a player has the line of the ball on his right, he has the right of way. This can be taken away by moving the player off the line of the ball by making shoulder-to-shoulder contact.
A player can:
hook an opponent’s mallet,
push him off the line,
bump him with his horse
or steal the ball from him.
The umpires’ primary concerns are right of way and the line of the ball.
The line of the ball is an imaginary line that is formed each time the ball is struck.
This line traces the ball’s path and extends past the ball along that trajectory.
The player who last struck the ball is considered to have right of way, and no other player may cross the line of the ball in front of that player.
Riding alongside to block or hook is allowed, as long as the player with right of way is not impeded.
Ride Offs
Bumping or riding off is allowed as long as the angle of attack is less than 45 degrees, and any contact must be made between the pony’s hip and shoulder.
Hooks
A player may hook or block another player’s mallet with his mallet, but no deliberate contact between players is allowed. A player may not purposely touch another player, his tack or pony with his mallet.
Safety
The mallet may only be held in the right hand. Left handed players are often thought to hit with less accuracy, but guide their ponies better than their right handed peers.
Ponies play for a maximum of two chukkers per match.