[%c_effect g4;square;g4;type;Interesting;persistent;true] A surprising and fresh idea. In the long history of this defense that has been played for ages, this is not an easy feat. This move was played by Carlsen in 2023, and no doubt its theory will develop quickly.
1. c2c4  1... e7e6  2. b1c3  2... d7d5  3. d2d4  3... g8f6  4. c4d5  4... e6d5  5. c1g5  5... f8e7  6. e2e3  6... h7h6 The Queen's Gambit Declined is probably the classical defense that has changed the most in recent years, with new plans for the black side being discovered. 7. g5h4 