When the bishop is actively positioned on the a1-h8 diagonal and obstructs the approach to the g-pawn, i.e. threatens with a back-rank attack on the opponent’s pawns, White will have to show the highest skill to realize the win. As an illustration, let us see the Radev – Pribyl endgame ( Tbilisi, 1971 ). This very example best reflects the theorem which says that the stronger side is even stronger with more pawns on the board. Without the f-pawn, this would be a «hard» draw because the bishop and king do not allow the approach to the g-pawn. Believe it or not, the position is won thanks to the pawn’s breakthrough.