Originally posted by WulebgrThe general method remains the same. The b5 pawn is traded for the c6 pawn, the wK advances, then the c5 pawn is traded for the a7 pawn. After that, Black cannot get the opposition in a useful way. He will be squeezed off the d5 pawn and lose.
4...Kc7 appears more stubborn.
Against 4...Kc7, White can simply play 5.Ka5, threatening 6.bxc6 Kxc6 7.Ka6, winning easily, or he can even play 5.bxc6, which is not quite as fast as 5.Ka5, but still appears winning.