With the b-pawn on the sixth rank White’s prospects of winning are much lesser since the knight’s defence capability increases by getting away from the rim. It should be noted right from the start that the passive defence with the king on the back rank is not good since the lack of manoeuvring room will eventually decide. The black king is “asphyxiated” and at first glance it appears that it can put up some resistance by defending by stalemate i.e. constantly offering the knight. Although White cannot breach the blockade of the critical square b7, the hidden mating motif ( i.e. Kc8 followed by Nc7 ) decides.