Sweet puzzle, the key move is not so obvious.
Thanks for sharing.
Grunfeld isn't always the so admired model of Kasparov and others
that play such opening...!
That is brilliant.
Didn't see a5 in advance, but got it otherwise.
Genius! at first i thought Nb4 was a clear win, (after fumbling around for 20 seconds for the right plan) i missed a5, then felt that Nd5 looked good, i played it and right away saw that there was Nf6+. Nice game!