Simple but Hard Puzzles

Endgame mate-in-two problems can be quite difficult. Even ones that are suppose to be below my skill level.
Perhaps it's because it uncommon for my games to get to the late stage endgame. When I do, it can be electrifying: suddenly the kings jump into action, pawns start to race, and a single tempo often means the difference between the ecstasty of victory, or the agony of defeat.
White to move and mate in one.
White to move and mate in one