6.1 - Basic Return Rule
In general, the ball remains in play as long as
it is bouncing. However, the player may swing only once at the ball and
the ball is considered dead at the point it stops bouncing and begins
to roll. Also, anytime the ball rebounds off the back wall, it must be
struck before it crosses the short line on the way to the front wall,
except as explained in Rule 6.2.