Was it a strike?

[Smiley]

Technically, it doesn't have to break the front plane, but usually, it does. The requirement is that any part of the ball passes through the zone, which is defined as the space over the plate and between the forward armpit and the knees. This is a cubical space, which a part of the ball must pass through. It could theoretically enter from any of 5 sides (not the back plane), and exit through any of the other sides. It does not need to stay above both knees.