[%c_effect g5;square;g5;type;GreatFind;persistent;true] This is exactly why the pin was formerly considered bad for White. Black advances the pawns on the missing king to gain time, and what is the bishop doing on g3 $2 Even more so after the white king is castled. But the explanation is simple: the computer shows that everything in this life is possible, and the players are making the dogmas of the past more flexible.
1. e2e4  1... e7e5  2. g1f3  2... b8c6  3. f1b5  3... a7a6  4. b5a4  4... g8f6  5. d2d3  5... f8c5  6. c2c3  6... d7d6  7. c1g5 These Bg5-pins are now played in all positions. In my day this was considered superficial, an amateur move that can't resist a pin. Times have changed; I must refresh my chess knowledge. 7... h7h6  8. g5h4  8... c5a7  9. b1d2  9... c8d7  10. e1g1  10... d8e7  11. b2b4 