Pause after Separation

[RKBUmp]

FED 6-2 says the pitch starts when one hand is taken off the ball or the pitcher makes any motion that is part of the windup after the hands have been brought together.

6-4-a says the pitcher may make no motion to pitch without immediately delivering the ball.

I would say separating the hands starts the pitch and would be considered a motion to pitch, requiring the ball to be delivered immediately. I believe the pause would be an illegal pitch.