Amazing. I've been stuck on this since the OP first posted. Interesting history nd flat out fun to watch even if I don't know the rules of which there seem to be not too many. I love the respect each side has for each other, knock the dude goofy then help him out until he's OK
The rules are... that there is no rule.
There are two teams of 27 players, and one ball. Each team has to shoot (hands or feet doesn't matter) the ball into the opponent's goal (which is a net running along the whole end of the field).
They can do anything to score a goal and to prevent the opponents from scoring.
So, violence is the normal gameplan
They should get MMA Fighters as their players then.