The "Queen's Gambit Declined" is a popular chess opening that arises after the moves 1.d4 d5 2.c4 e6. In this position, Black chooses not to accept the pawn offered by White, opting instead to maintain a solid pawn structure. This decision leads to a rich and strategic battle, allowing both players to develop their pieces effectively. This opening is favored by many players, including grandmasters, due to its resilience and flexibility. It often leads to complex middlegame positions where both sides have chances to outmaneuver each other. The Queen's Gambit Declined is a key part of classical chess theory.