5-a-side Football at the Paralympics is for visually impaired athletes, and consists of eight teams of five players competing in a Group/Knockout tournament.
Though it's based on the traditional game of Soccer, 5-a-side football has its own rules. Four outfield players and a goalkeeper compete on a pitch divided in to thirds, with each team allowed a sighted guide per third to call out instructions. The pitch itself, much smaller than a normal football pitch, is surrounded by a rebound wall, and there are no throw-ins or offsides, so the action can be quite relentless.
Most importantly, the ball makes a sound when moving, so players can hear it and are aware of its location.
Although players with varying degrees of visual impairment feature, all four of the outfield players must wear blackout masks to ensure fairness. The goalkeeper may be sighted, and can act as one of the sighted guides.