Rook Endings That Every Tournament Player Should Know

The first two positions are incredibly important for the tournament player. The last one, the Vancura Position, is a defensive technique that some IMs (International Masters=rating 2400+) and many masters and surprisingly strong players do not know.

Try these positions out against friends or here: http://www.shredderchess.com/online-chess/online-databases/endgame-database.html <-- A great endgame resource