This cartridge plays the basic version of Super Tennis without on-screen scoring. The game is somewhat hard to play because there is no manual serve, hence a continuous game. The ball speed increments as far as the players catch the ball, and the system produces a beep when the ball is lost.
One might wonder why this cartridge contains seven more chips than Badminton. As a matter of fact, the differences with Badminton are the player motions (vertical only in Badminton, bi-directional in Tennis), the condition the system uses to produce a beep (when the ball is cought in Badminton, or lost in Tennis), and finally the central line (net) which is indeed thiner than the wall in Sparring. The answer is simple: by design, the system can only produdce two players (of variable size) and a ball, hence the need of additional chips to draw the central line in Tennis. Sparring does not require those chips because the second player has an infinite height to form a wall, hence its same width than the player.