Tackling is similar to American football, except that there's no blocking in rugby. Once a player is tackled, if he can't pass (sideways or backwards), there'll be a 'ruck.' This is when other players join around to protect the ball, keep it moving forward and re-distribute it to start another play. Rugby keeps going until play stops for an error or
offense, or the ball goes out of play.
Unlike football, in rugby you can only pass the ball laterally to another player, or behind you. A forward pass is an infringement
that will result in a scrum.