A golf swing improvement tool is provide that attaches to a golf club, and includes a guide arm contacting the leading forearm of a golfer. An offset arm allows the guide arm to be offset laterally from the longitudinal axis of the golf club. The user adjusts the offset distance to give a specific leading arm-to-club relationship. If the club moves ahead of the desired relationship with the leading arm during the swing, the user will be alerted to this error by the guide arm loosing contact with the forearm.