hey is it **hard** for u all??

it is actually from one of the exercise in Artur Yusupov's Build Up Your Chess 1, which is in chapter 9 ( mate in 2 move ) , that is about **CALCULATING VARIATIONS**.

all the exercises are only rated 1 star, but i find it to be the hardest checkmate puzzle that i ever solved, some i took over 20+ minutes !!! is it really hard?? or my calculation really really weak??

now set the clock and find the shortest mate, which is 2.

after doing it, tell me your rating and time taken to solve each puzzle, and your comment about it ( very hard, hard, medium, easy )