Rook plus a-pawn and three kingside pawns against rook and three kingside pawns, with the attacking rook in front of its pawn, was long thought drawn; Steckner showed that the attacking king can march to the queenside and that a rook sacrifice on the c-file wins.
This structure is a landmark of modern rook-ending theory. White has an extra a-pawn on a6 with the rook stuck in front of it on a7, and Black's rook on a2 is behind the pawn, exactly the configuration that is normally a draw when the pawn is a lone rook pawn. With three pawns each on the kingside, Kantorovich analysed the position in 1989 and concluded that Black held. In 2003 Steckner found that the king march wins in a critical line, and the result was re-evaluated.