Chess Opening Theory/1. d4/1...Nf6/2. c4/2...e6/3. Nc3/3...Bb4/4. Qc2/4...d5/5. a3/5...Bxc3/6. bxc3

6. bxc3 Nimzo-Indian Defense: Classical, Noa Variation, Pretzel Gambit rd nd bd qd kd rd pd pd pd pd pd pd pd nd pd pl pl pl pl ql pl pl pl pl rl bl kl bl nl rlThe Pretzel Gambit (unofficial title, unrecognized in the Encyclopedia of Chess Openings) is a slightly dubious and semi-obscure gambit that allows white to play 2 different types of positional games that otherwise wouldn't occur in the main line after 6. Qxc3. while the better move after bishop takes is Qxc3, Stockfish 18 on medium depth evaluates it as completely equal (0.0 – -0.1). 6… dxc4?! While 6…dxc4?!, taking the free pawn, looks like the best move in this position, the engine evaluates it as the 4th best move in the position, giving up whatever little advantage black had. This is because the following move for white in this position is e4! gaining central space black will not gain back, and planning to go e5 attacking the knight. This position slightly resembles a Queen's Gambit accepted, but with a few key differences. The gambited pawn will not be won back, as it can be defended with b5. The c-pawn (previously the b pawn before takes) defends the d pawn and prevents the black c-pawn from advancing. the queen supports the e4 push instead of the knight Funnily enough, contrary to fundamental theory in the Queens Gambit accepted, the main line is to defend the weak pawn with 7... b5, because after 8. a4 (the best move for white) the only move to keep the game equal for black is 8… Bb7! applying pressure on the e-pawn, but better yet applying permanent pressure on the long diagonal. If/when white castles, they (99 times out of 100) have to castle kingside due to the weakness of the queenside, and in the future if the e-pawn ever moves, the light squared bishop will always have its sights on the king. 6… O-O O-O is the engine favorite move (on cloud depth) of many good replies to the gambit. 7. cxd5? while not immediately losing is a very dubious and dangerous move for white. This is because: After 7... exd5, e4 is no longer a move for white and, no matter what move you play, c5! is the immediate response; the queenside is very weak and white is undeveloped. After 6... O-O there are two simple moves the engine prefers: 7. e3, supporting the weak pawn or 7. Nf3 !? reinviting the gambit and developing a piece. If black takes the "free" pawn, they are much worse due to the fact that 8. e4! comes with a venom it didn't have earlier in the position. now white can attack with initiative. The best move following both e3 and Nf3 is c5, a very uncanny Tarrasch type of position where white somehow has a queen on c2 and doubled pawns on c3 and c4. after e3 and Nf3 are played (something like 6... O-O 7. e3 7... c5 8. Nf3) the computer recommends b6, and the ensuing lines are unfathomable and kafkaesque in nature, with: 8... b6 9. dxc5!? 9... Ba6!? 10. cxd5!? 10... Bxf1 11. Kxf1!? 11... Qxd5 12. cxb6! 12... axb6. 6... c5 Theory table {{Chess/theory table |eval1= |line1=6. dxc4 7. e4 7. b5 8. a4 8. Bb7 9. f3 9. a6 10. Qb2 10. Nbd7 |name1=Exchange variation |eval1= |line2=6. O-O 7.e3 7. c5 8. Nf3 8. b6 9. dxc5!? |eval2=unclear |name2=Wind variation }}