Question 6. What do they call the opening play in polo?

In hockey, it’s a face-off, in basketball it’s the tip-in, but in polo it’s known as the throw-in.  The umpire tosses the ball in between the two teams as they line up parallel to one another.  In earlier days, the custom was to place the ball in the middle of the field and have two opposing players charge it from opposite directions.  This practice was eventually discontinued, probably because of incidents like the one that occurred in 1888 at Myopia Polo Club in Massachusetts.  Living up to the club’s name, the riders charged myopically at the ball and collided head-on, knocking one of them out cold.