Normal Defense

By answering 3. Nc3 with 3...Nf6, Black brings out the king's knight, gets ready to castle short and adds pressure on e4. The position is the central junction of the Queen's Gambit Declined. Most of its principal systems branch from here, and several of them can transpose into one another. Black has not yet committed to ...c6, ...c5, ...dxc4 or ...Bb4, so the choice of structure is left until White has shown a plan. White's own decision on the fourth move largely fixes the character of the game.

The most frequent reply is 4. Nf3, the Three Knights Variation. It keeps every option open and gives Black a wide menu. Black can choose 4...c6 (Semi-Slav), 4...dxc4 (Vienna), 4...Bb4 (Ragozin) or 4...c5 (Semi-Tarrasch), and some of these lead to the sharpest play in the whole complex. The quieter 4...Be7 can return to Bg5 lines after 5. Bg5, though White may prefer 5. Bf4.

4. Bg5, the Modern Variation, develops the dark-squared bishop outside the pawn chain before e3 locks it in, so the light-squared bishop can then be released. Black normally breaks the pin with 4...Be7 and castles. After 5. e3 O-O 6. Nf3 the main fork is between 6...Nbd7 and 6...h6. An independent path is 4...Nbd7, which after 5. e3 c6 6. Nf3 Qa5 gives the Cambridge Springs Defense, where Black uses the pin on the c3-knight for counterplay.

4. cxd5, the Exchange Variation, is the engine's first choice. After 4...exd5 Black's queen's bishop gains an open diagonal, but the Carlsbad structure that follows offers White clear plans, chiefly the queenside minority attack. It is not a drawish exchange line. 4. Bf4, the Harrwitz Attack, is a less common alternative that posts the bishop actively without pinning the knight.

The engine rates the position as roughly balanced, with a small plus for White. On Lichess, White wins 51% of games against 44.5% for Black, and draws are rare in that sample. Among the thousands of named openings, few positions are reached more often.