PROBLEM TO BE SOLVED: To provide a ball that makes a player recognize the direction to hit the ball and the direction of rotation to be provided to the ball through a visual image, and makes the player move one's body so as to move the ball to the target direction accurately, in the practice of a competition or in the competition using the ball.SOLUTION: A first arrow 130 showing the direction desired to carry the ball and an annular second arrow 150 showing the rotation direction to be provided to the ball are provided in the inside of a transparent ball 100. Alternatively, the display projecting the first arrow and the second arrow on the ball surface is provided on the surface of an opaque ball or a transparent ball. Also, the first arrow and the annular second arrow surrounding the first arrow are provided in the inside of a transparent spherical shell in order to describe the operation of the balls. The inclination to the first arrow of a transparent plate provided with the second arrow is made variable.
