 It is often seen in the endgame, for example in endings with bishops of opposite colors (see above).In Arshak Petrosian–Hazai, Schilde 1970 (left-most position), Black has a difficult endgame, since White can attack and win his a-pawn by force, and he has no .Realizing how difficult his position was, Black tried the amazing 45...Qb6 White replied with the obvious 46.Nxb6+?, but this was actually a critical mistake, enabling Black to establish a fortress.