[Event "Opening Traps in the Blackmar-Diemer Gambit: #1 Halosar Trap"]
[Site "https://lichess.org/study/MnFMDaGt/L7TOP7cM"]
[Date "1934"]
[Round "?"]
[White "Diemer, Emil Joseph"]
[Black "Halosar, Hermann"]
[Result "1-0"]
[Annotator "https://lichess.org/@/Jonnyx"]
[ECO "D00"]
[Opening "Blackmar-Diemer Gambit Accepted: Ryder Gambit"]
[UTCDate "2020.06.12"]
[UTCTime "13:31:08"]
[Variant "Standard"]

{ You can watch the analyse of the game as a video aswell: https://www.youtube.com/watch?v=Di83DvQQsEs The Halosar Trap is named after Herrmann Halosar, who lost a game against Emil Joseph Diemer himself at Baden-Baden in 1934. } 1. d4 d5 2. e4 { The starting position of the Blackmar-Diemer Gambit. } 2... dxe4 3. Nc3 Nf6 4. f3 exf3 5. Qxf3 { This variation is known as the Ryder Gambit. White offers black a second pawn and hopes to get a fast development, but I think with best play white has serious problems proving enough compensation for the sacrificed pawns. } ( 5. Nxf3 { is the mainline of the Blackmar-Diemer Gambit. Here black had tryed out many different moves. I will not cover them in detail in this analyse, but if you click on the book symbol under the notation, you will find some grandmaster games. Good moves for black would be for example: } 5... Bf5 { known as the Gunderam Defence. } ( 5... Bg4 { known as the Teichmann Defence. } ) ( 5... e6 { known as the Euwe Defence. } ) ( 5... g6 { known as the Bogoljubov Defence. } ) ( 5... c6 { known as the Ziegler Defence. } ) ) 5... Qxd4 { Black has no fear and takes the second pawn. } 6. Be3 Qb4 ( 6... Qg4 $5 { even if the text move isn't bad, this move is probably even stronger. White really doesn't want to swap queens because then he wouldn't have any compansation for the two pawns. So he's more or less forced to play } 7. Qf2 { but after } 7... e5 { I don't think that white has enough compansation for the two pawns. Check out the game Kireev vs. Kund played in 2006 if you want to know more about this position. } ) 7. O-O-O Bg4 $4 { This move is tempting because it looks like black is winning at least an exchange, but the truth is, that black is now clearly losing. Funny enough this move was played in in nearly 900 games that reached this position on Lichess. This is equal to about 50%. A better move would have been [%cal Rg4d1] } ( 7... c6 { to stop any Nb5 threats by white. } ) 8. Nb5 $1 { Now black is losing. [%cal Gb5c7] } 8... Na6 ( 8... Bxf3 $4 { fails to } 9. Nxc7# ) 9. Qxb7 { [%cal Gb7a6,Gb7a8] } 9... Rc8 ( 9... Qe4 { [%cal Re4a8] } 10. Qxa6 Qxe3+ ( 10... Bxd1 11. Kxd1 Rd8+ 12. Bd2 Rxd2+ { if black doesnt give up the rook he's in big trouble. } ( 12... e6 13. Nxc7+ Kd7 14. Qxa7 Bd6 15. Bb5+ Ke7 16. Ne8+ Kf8 17. Nxd6 Rxd6 18. Nf3 Rd8 19. Qc7 { and white is allready clearly winning. } ) ( 12... Qe5 { protecting the pawn on c7 only speeds up whites attack against blacks king. } 13. Nf3 Qc5 14. Qb7 { threatening again to take on c7 with the knight. [%cal Gb5c7] } 14... Nd5 15. Nd6+ $3 { WHAT A MOVE!!! } 15... Rxd6 ( 15... cxd6 16. Bb5+ Qxb5 ( 16... Rd7 17. Qxd7# { fails to } ) 17. Qxb5+ Rd7 18. Qxd5 { White is up a queen and a knight for a rook. White is winning winning. } ) ( 15... exd6 16. Bb5+ Ke7 17. Re1+ Kf6 18. Bg5+ Kg6 19. Bd3+ f5 20. Bxd8 { White is up a piece while blacks king is still in grave danger. White is winning. } ) 16. Bb5+ Qxb5 ( 16... c6 17. Qc8+ Rd8 18. Bxc6+ Qxc6 19. Qxc6+ Rd7 20. Ne5 { [%cal Gc6d7] } 20... Nb6 21. Nxd7 Nxd7 22. Qc8# ) ( 16... Rd7 { fails to } 17. Qc8# ) 17. Qxb5+ { White is up a queen for a rook while blacks king is still in grave danger. White is winning winning. } ) 13. Kxd2 Qf4+ 14. Ke2 ( 14. Ke1 $4 Qc1+ 15. Kf2 Ne4+ 16. Kf3 Ng5+ 17. Ke2 Qxc2+ 18. Ke1 Qc1+ { black rescued himself in a perpetual check. } ) 14... e6 15. Nf3 { and white is up a piece. } ) 11. Kb1 { white threatens Nxc7 mate. [%cal Gb5c7] } 11... Qc5 12. Qb7 { threatening to take the rook on a8 with the queen or the pawn on c7 winning the queen. [%cal Gb5c7,Gb7a8] } 12... Bxd1 13. Qxa8+ Kd7 14. Nc3 { and blacks best move is actually 14... e6 giving up the bishop on d1. } 14... e6 ( 14... Bg4 15. Bb5+ c6 16. Qb7+ Ke6 ( 16... Ke8 17. Bxc6+ Kd8 { and blacks king is in grave danger. [%cal Gg1f3,Gh1d1] } ) 17. Bxc6 { and blacks king is in grave danger. If you still have doubts just turn on the engine and try to defend the position as black. [%cal Gg1f3,Gh1e1] } ) 15. Nxd1 { White is up a piece and should win the game. } ) 10. Qxa6 { black surrendered because he's allready down a piece and still has to face to many threats. For example: } 10... Bxd1 11. Qxc8# 1-0