1 
2 3
4
5
6
7 
h 
g 
f 
e 
d c b 8 a ←→ to step through moves · Home / End — first / last
Why it works
Taking on d5 is the most natural move in the Grünfeld and 12% of players below 1200 take it here — the difference is the bishop on f4, which has been left hanging on a diagonal the knight is about to hit. 6...Nxd5 7.e4? Nxf4 costs a piece straight away, and 8.Bc4 Nxg2+ takes a pawn with check on the way out. The knight that looks like it is wandering into the centre is actually collecting White’s two loose pieces one after another.
Refutation
6.e3 first — the modest move that gives the f4-bishop a retreat and is the choice of 60% of players, scoring 53%. 6.h3 (54%) and 6.Nb5 (53%) also hold. The pattern: do not open a file for the enemy knight while your own bishop stands undefended on it.