Pokémon Black and White/Rotation battles
From StrategyWiki, the video game walkthrough and strategy guide wiki
Rotation battles are easy to understand and slightly easier to explain.
You and your opponent each have three Pokemon (we will use Snivy, Tepig, and Oshawott as the players Pokemon)
Snivy is in front, so Snivy is the attacking/damage receiving Pokemon. but don't fret, you can rotate to either Tepig or Oshawott so the are the ones who attack instead.
if you are concerned that only the front Pokemon will receive Exp. then forgett about that because ALL of the Pokemon in battle get Exp. (so you can level up your whole team!)
Rotation Battles are found in the Battle House in Pokemon Black Version.
