[%c_arrow f8b4;keyPressed;none;from;f8;opacity;0.8;to;b4;persistent;false,d4d5;keyPressed;ctrl;from;d4;opacity;0.8;to;d5;persistent;false] This is the so-called Petrosian Variation of the Queen's Indian Defense. The idea behind ​​White's fifth move is to avoid the pin with ...Bb4, now creating the positional threat of playing d4-d5, gaining space in the center. This line was a favorite of the young Garry Kasparov, and I remember studying as a teenager some beautiful wins in his fabulous book \"The Test of Time.\"
1. g1f3  1... g8f6  2. c2c4  2... b7b6  3. b1c3  3... c8b7  4. d2d4  4... e7e6 