many do not understand this rule. From the set position (one of the two legal pitching positions) he may throw directly towards a base as long as he first steps towrds the base he is throwing at before he delivers the ball. He may also do this same thing from the windup position- at least in pony league rules. A lot of coaches teach that when you see the front leg move first to take off because he now has to pitch home. This is obviously not the case as lefties step and throw from the set position all the time.
As far as moving the front leg first and then jump spinning- perfectly legal. The sound logic is always that there was no ill intent to decieve the runner. Any good coach will teach his players that on first with a rhp you do not get a big lead or run until the pitcher has moved his front leg into a position that then requires him to pitch home. The pitcher has to have some ability to legally try to pick off runners and be deceptive all the while being legal about it, otherwise the advantage would always go to the runner.
Tonight in our city game I had the opposing coach conitnually trying to sway the umpire into calling my pitcher for a balk- here was the situation- runner on second with two out. The runner is obviously trying to get as big as lead as possible so that he can score on any hit or mistake. My pitcher knowing this will after he has come set, look directly at the catcher and go into his windup only he will turn his back completely to the batter as if he is going to make a throw towards second. This is all done as he is raising his stride foot. At the top of his leg kick and with his back all the way turned towards the batter he will suddenly look at second freezing the runner or even causing him to dive back. But instead of throwing to second,, my pitcher will just complete his leg kick, look back towards home and fire a strike to the unsuspecting batter, which also catches the batter off guard. It is all done in one smooth sweeping motion with no hesitation or pause.
The opposing coach says that my pitcher can't do that because he hasnt pitched that way until a runner gets on second and he says that is decieving the runner and is a balk. My defense is that as long as he doesn't hesitate, jerk or pause unaturally he can change his leg kick and amount he turns his back to the batter as much or as little as he wants. The pitcher doesn't have to have the same exact pitching motion every time. A good pitcher could have 10 or more different motions in his delivery to try to keep runners close at second.