Something I thought of when teaching my friend how to play tennis, telling him the basic grips and such. Told him eastern grips hit flatter, the more to the west (While twisting the racket in his hand) you go, the more topspin you get. That's fine. I won't dispute it. But what exactly causes it? Does it have to do with the positioning of the wrist? A change in contact point? I feel that understanding a seemingly fundamental question can lead to insight on tennis as a whole, as asking "what really produces spin" can, what I feel, help in other aspects of the game as well. My thoughts: I've always felt that spin is produced by the swing direction. Straight and simple. In my mind, changing your grip simply forced you to swing in a more upwards swing path in order to hit the ball cleanly, thereby forcing you to hit with more spin. My thinking was supported when I saw players like Federer, who with seemingly tame grips would still hit monstrous amounts of spin. My own finding on the courts, that I could produce ample spin with a eastern-semiwestern crossover (which I believe is called classic?) grip, and not particularly more with a western (Although that could very simply be that I don't know how to use one). When viewing players such as Nadal, however, it is clear that they hit with more spin. Is this really a result of their grip, or are they doing something inheirently different than the rest of us? By answering such questions, my hope is to shed light on what really goes on in a swing, and how that produces certain balls.