Reiji Shinjou is known as Hanamura's greatest "masterpiece", with his techniques involving very powerful shots known as Mirage. The powerful shots are indistinguishable from a regular return or serve, leaving opponents confused. Another technique he has is the Deep Impulse, which is a powerful shot that also can be used as a serve that will injure the opponent, and consecutive attempts to return the Deep Impulse may injure the player to the point of unable to play tennis anymore.

Source: Wikipedia