9.2 Throw in provisions

[tref]

Hmmm good one, perhaps theres an old interp?

I would think that the bottom of the backboard could be considered the bottom "side." It's definitely inbounds...

[Jurassic Referee]

The bottom of the backboard, by rule is in-bounds and in play. There was an old interp floating around years ago that said that the administering official should watch which way the ball rebounded off the bottom of the board on a throw-in. If the ball rebounded straight down or out onto the court, it had to have hit the bottom of the board and thus was a legal throw-in. If instead, the ball rebounded back towards the end line, the ball must have hit the back of the backboard and thus had to be a violation.

Simple physics iow.