Illegal or not?

[EricH]

The reason for the rule is to keep the pitcher from stepping on the rubber and immediately pitching or something similar. If she steps on, takes the sign, and brings her hands together AFTER 1 second, she has fulfilled her pause responsibility. The batter is responsible for being ready by the time that 1 second pause has ended. As others have said, if the batter has one foot out, hold the pitcher until both feet are in the box, and then signal to play. At that time the pitcher can immediately begin the pitch if she has already paused and brought her hands together.