If at all Black promotes one of his pawns to a queen or even a rook, he checkmates White!
Not only White must queen his pawn first but also with a precondition that it should be done well in advance to go and stop Black from queening
White must queen at f8 square to gain a tempo by the check to Black king!
If the pawns after exchange end up in opposing each other without a chance of creating a passed pawn, Black king is in a better position to grab them.
During a Training Session Chess master Gary Lane, showed this to our
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