The Saavedra position is one of the best known and very famous chess endgame studies. The position involves a King and pawn on the 6th Rank vs a Rook and King. It was thought to be drawn as the Rook could always sac itself for the pawn leading to insufficient material. But it was later discovered that White could actually play for a win and find a way to promote his pawn before the Rook can capture the pawn. See the technique used by white below to win this endgame.