New Zealand Chess Magazine, October 2018

The Blackmar-Diemer Gambit, by Nigel Cooper

Acknowledgement: The following notes under History and Variations include much material from Wikipedia's article on the BDG. It draws mainly from Christoph Scheerer's 2011 book, The Blackmar-Diemer Gambit: A modern guide to a fascinating chess opening.


Blackmar was a US chess player in the 19th century who used 1.d4 d5 2.e4 regularly. If Black plays dxe4 Blackmar played 3.f3 offering a gambit pawn. This proved to be unsound, as Black immediately seizes the initiative with 3...e5! In the 20th century a German, Emil Diemer played this opening but used 3.Nc3 first. Then if either Nf6 or Bf5 to protect the black pawn on e4, he played 4.f3. This proved to be a better opening. After many years of analysis, Diemer wrote a book on the opening in the late 1950s, titled Vom Ersten Zug An Auf Matt! (Toward Mate From The First Move!). So the Blackmar Diemer gambit (BDG) was born. It has a fanatical following, with a regular blog on the opening written by Guido de Bouver of Belgium He is one of many authors who have published books on the BDG.

Emil Diemer had a brilliant attacking style. Several books have been published on his games. Here are some of his smashing victories.

Deimer - Toth 1948

1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Qxf3 Qxd4 6.Be3 Qb4 (6...Qg4 is better ) 7.O-O-O

Moves are clickable

7...Bg4? This is the Halosar trap, discussed later  8.Nb5 Na6 9.Qxb7 Rb8 10.Qxb8+ Nxb8 11.Nxc7# 1-0

In 1979 against an unnamed player, he won even quicker:

Diemer - NN 2018

1.d4 d5 2.e4 dxe4 3.Nc3 e5 4.Nxe4 exd4 5.Bb5+ c6 6.Bc4 Be6 7.Qe2

Moves are clickable

7...Bxc4?? 8.Nf6# 1-0

And just for fun to see how he played as black, here is a win in 13 moves, having sacrificed three pieces:

NN - Diemer 2018

1.d4 e5 2.Nf3 e4 3.Nfd2 d5 4.c3 Bd6 5.e3 Nf6 6.Be2 c6 7.O-O h5 8.f3

Moves are clickable

8...Bxh2+ 9.Kxh2 Ng4+ 10.fxg4 hxg4+ 11.Kg1 Rh1+ 12.Kxh1 Qh4+ 13.Kg1 g3 0-1


After playing the opening moves  1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Nxf3

Moves are clickable

there are at several moves possible for Black. There is no definitive 'best' move here, and therefore that makes it all the more difficult for both sides to play the opening, as there are several alternatives at almost every move. The opening suits players who can think quickly over the board, like attacking, taking risks, and who desire short games, either winning or losing quickly! 

Gunderam Defence

1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Nxf3 Bf5 Gunderam Defence The main response for White is  6.Ne5 intending to attack the Black bishop with an advance of the kingside pawns and weaken Black's kingside pawn structure with Ne5xBg6. Black can respond with (  [An alternative response to the Gunderam defence is 6.Bd3 when play usually goes  6...Bxd3 7.Qxd3 c6 8.O-O e6 with about equal chances.] ) 6...e6 when after  7.g4 Be4

Moves are clickable

leads to tremendous complications e.g. after ([ 7...Bg6 is more common and leads to quieter play, White's best response is probably  8.Bg2 c6 9.h4 with a sustained kingside initiative in return for the pawn] ) 8.Nxe4 Nxe4 9.Qf3 Qxd4 10.Qxf7+ Kd8 11.Qf4

Teichmann Defence

1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Nxf3 Teichmann Defence  5...Bg4 By pinning the knight on f3, Black intends to swap it off and undermine White's central control. White's best response is to attack the bishop immediatelywith  6.h3 when play often continues  6...Bxf3 (  If Black retreats the bishop with 6...Bh5 7.g4 Bg6 8.Ne5 a line which often transposes to the Gunderam Defence line 5...Bf5 6.Ne5 e6 7.g4 Bg6 after a subsequent h3-h4, as White's extra tempo with h3 is not particularly useful. ) 7.Qxf3 c6 (but not 7...Nc6, when 8.Bb5 is good for White). In this position, White can defend the attacked d-pawn with  8.Qf2 (the Ciesielski Variation), but this allows Black an easy game by preparing ...e7-e5, e.g. after ( Alternatively 8.Be3

Moves are clickable

is the Classical Variation, where White aims for a slow buildup to a kingside offensive. ) ( White's other main alternative is 8.g4!? the Seidel-Hall Attack, where White is happy to sacrifice the d-pawn in order to gain an increased initiative on the kingside, e.g. after  8...Qxd4 (  Black can decline the pawn, e.g. after 8...e6 9.g5 Nd5 10.Bd3


leading to sharp play. ) 9.Be3 Qe5 10.O-O-O e6 11.g5 ) 8...Nbd7 9.Bd3 e5

Lynn, William - Power, Wayne New Zealand Championship 1976

1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Nxf3 Bg4 6.h3 Bxf3 7.Qxf3 c6 8.Be3 e6 The Classical Variation of the Teichmann Defence.  9.Bd3 Be7 10.O-O Nbd7 11.g4 h6 12.Ne4 g5 13.Rf2 Qc7 14.Raf1 O-O-O 15.Nxf6 Nxf6 16.c4

Moves are clickable

16...Rdg8 Either 16...c5 or ...h5 give Black an edge. The move played is about equal.  17.Qg2 Qd8 18.b4 h5 19.b5 c5 20.Be4 Nxe4 21.Qxe4 hxg4 Black is on +1, but White keeps attacking.  22.Rxf7 Qd6 23.Qxg4 Rh4 24.Qg2 cxd4 25.Bf4


25...e5 (25...Qa3 better ) 26.Bg3 Rhh8 (26...Rh6 retains the initiative. ) 27.R1f5 d3 28.Qd2 g4 29.h4 Bxh4? (29...Rf8 leads to two rooks vs queen endgame, which Black should not lose. ) 30.Bxe5 Qc5+ 31.Kf1 (31.Kg2 leads to a forced win more quickly. ) 31...Be7 32.Bxh8 Qd6 33.Be5 Qa3 34.Rxe7 Qxe7 35.Qxd3 1-0

Lynn, William - Duneas, John Waikato Open-A 2012

1.e4 Nf6 The Alekhine Defence.  2.Nc3 d5 3.d4 The BDG can be transposed from White opening with e4 and Black responding with the Scandinavian Defence d5. If you don't like playing against the Scandinavian Defence you can now play d4 and you will have a BDG, probably annoying your opponent, who may not have replied 1...d5 to 1.d4.  3...dxe4 4.f3 exf3 5.Nxf3 Bg4 6.h3 Bxf3 7.Qxf3 c6 8.Be3 e6 9.Bd3 Nbd7 10.O-O Be7 11.Ne4

Moves are clickable

11...O-O 12.c4 Nxe4 13.Qxe4 g6 14.Bh6 Re8 15.Rae1 Bg5 16.Bxg5 Qxg5 17.h4 Qe7 18.Qf4 Rad8 19.Re3


It's a good thing players don't have computer evaluations of their positions. Up to this point, Black has a +1 advantage. But he starts to lose it now with.  19...c5 20.d5 e5 21.Qg3 Nf8? (21...Kg7 keeps Black in the lead. but now White takes over the initiative. ) 22.h5 Qd6 23.Be4 Nd7 24.Ref3 Rf8 25.Qg5 Rde8 26.Rh3 Qe7 27.Qh6 f5 28.d6 Qg7 29.Bd5+ Kh8 30.hxg6 Nf6?


After this blunder, White could win swiftly with Qg5! However he doesn't see it.  31.Rxf5 Qxh6 32.Rxh6 Kg7 33.gxh7 Kxh6 34.h8=Q+ Rxh8 35.Rxf6+ Kg5 36.Rf7 b6 37.Rxa7 Rh6 38.Re7 Rhh8 39.Bc6 Rd8 40.Rxe5+ Kf4 41.Re4+ Kg5 42.d7 Kf5 43.a3 Rxd7 44.g4+ Kg5 45.Bxd7 Rd8 46.Re5+ Kf4 47.Rd5 1-0

Euwe Defence

1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Nxf3 e6 The 5...e6 line aims to reach a French Defence type position, but with Black having an extra pawn. Play usuallycontinues  6.Bg5 Be7 when White's most popular option is  7.Bd3 Black can attack the centre immediately with  7...c5!? here. Play can continue  8.dxc5 Qa5 9.O-O Qxc5+ 10.Kh1

Moves are clickable

White has to play accurately to prove compensation for the pawn. Alternatively, on move 6, White can play Bd3, Be3, Bb5+ or a3. Each off these leads to numerous possibilities. 

Bogolyubov Defence

1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Nxf3 g6 By fianchettoing the king's bishop Black aims to gain increased pressure against the d4-pawn following a subsequent ...c5. White's most common response is the Studier Attack,  6.Bc4 ( An alternative approach is to castle queenside, play Bh6 and then launch the h-pawn against the Black kingside. The best way to carry out this approach is via 6.Bf4 e.g.  6...Bg7 7.Qd2 O-O 8.O-O-O c5

Moves are clickable

Now  9.d5 a6 10.d6! gives White good chances. ) 6...Bg7 7.O-O O-O 8.Qe1


intending Qh4, Bh6 and piling pressure on the kingside, sacrificing pawns at d4 and c2 if appropriate. See William Lynn's third game below. However, after  8...Nc6 9.Qh4 Bg4! it is doubtful if White obtains enough compensation for the pawn against accurate play. 

Lynn, William - Marsick, Bruce NZ Correspondence Championship 1972

1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Nxf3 g6 Bogoljubov Defence  6.Bc4 Bg7 7.O-O O-O 8.Qe1 Studier Attack  8...c5 9.dxc5 Qc7 10.Be3 Nbd7 11.Qh4 Nxc5 12.Rae1 Ne6 13.Bb3 Qa5 14.g4 Blow the trumpets, here he comes!  14...Nc5

Moves are clickable

15.Ng5 h5 16.Bxf7+ Rxf7 17.Nxf7 Nxg4 18.Qxe7 Nxe3 19.Qe8+ Kh7 20.Ng5+ Kh6 21.Qxe3 b6 22.Rf7 Nb7 23.Ne6+ g5 24.Nxg7 Qc5 25.Qxc5 Nxc5 26.Ne8 Bg4 27.Rf6+ Kh7 28.Re7+ Kg8 29.Rg7+ Kh8 30.Rh6# 1-0

Ziegler Defence

1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Nxf3 c6 Most modern authors recommend this as Black's best answer to the BDG. The old main line runs  6.Bc4 Bf5 7.O-O e6 8.Ne5

Moves are clickable

when Sheerer says Black should avoid  8...Bxc2?! ( But instead play 8...Bg6! when White ends up with very little to show for the lost pawn. For example, attempting a quick attack afterby  9.g4 can get White in trouble. E.g.  9...Nbd7 10.Nxg6 hxg6 11.g5 Qc7!


12.Bf4 Bd6 13.gxf6 Bxf4 14.fxg7 Be3+ and White resigned in Porrasmaa (2070) vs. Lobzhanidze (2428). (Porrasmaa, incidentally, beat former world champion Anatoly Karpov in 2013 with the BDG. It was a handicap game, with Karpov having 4 minutes and Porrasmaa 16 minutes. The BDG has taken down some highly ranked players!) ) 9.Nxf7! However, IM Kevin Denny gives 8...Bxc2 an exclamation mark because after 9.Nxf7 Kxf7 neither 10.Qxc2 nor 10.Qg4 lead to advantage for White. My own analysis is that Black is also OK after  9...Bxd1 10.Nxd8 Kxd8 11.Rxd1 Kd7 and Black holds on to the extra pawn and slowly develops. This line is likely to lead to a draw. (Ed: In this line though it seems though that White can play 12.Re1 and win the pawn back immediately with some advantage) 

Ziegler Defence Continued

1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Nxf3 c6 6.Bc4 ( An important alternative is 6.Bd3 , usually intending to sacrifice a second pawn after  6...Bg4 7.h3 Bxf3 8.Qxf3 Qxd4

Moves are clickable

leading to sharp complications. (Although Black can transpose back to the Classical Variation of the Teichmann Defence with 8...e6 , since White's only good response is  9.Be3 Black can prevent this 6.Bd3 possibility by using O'Kelly's move-order 4...c6. ) ) 6...Bf5 7.O-O ( White also has the dangerous, though probably objectively insufficient, second pawn sacrifice 7.g4 analysed extensively by Stefan Bucker ) (  Instead of 7.O-O Lev Gutman proposed the alternative 7.Bg5 e6 8.Nh4!? Bg6 9.Nxg6 hxg6 10.Qd3 intending to castle queenside and tie Black down to the f7-pawn, promising long-term positional compensation for the pawn. ) ) 7...e6 Earlier we looked at 8.Ne5. Another attacking move for White is  8.Ng5 the Alchemy Variation, where Black has to be careful not to fall for various sacrifices on e6 and f7, but White probably does not get enough compensation for the pawnafter  8...Bg6 9.Ne2 Bd6

Ryder Gambit

1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Qxf3 White can of fer a second pawn with 5.Qxf3, but he might have problems proving enough compensation for the sacrificed pawns after  5...Qxd4 6.Be3 Qg4 (  The Halosar Trap (named after Hermann Halosar) is 6...Qb4 7.O-O-O Bg4? If White moves the queen to 'save' it, he loses. But  8.Nb5! threatening mate with 9.Nxc7#. The line continues  8...Na6 (  The Black queen cannot capture the knight because 8...Qxb5 9.Bxb5+ is check, gaining time for the White queen to escape the threat from the bishop  ) ( Amusing was the miniature B Bart vs Jennen 1948 8...e5 9.Nxc7+ Ke7 10.Qxb7 Qxb7 11.Bc5#

Moves are clickable

) 9.Qxb7 Qe4


10.Qxa6 Qxe3+ (Worse is (10...Bxd1 11.Kxd1 Rd8+ 12.Bd2 and White is winning, for example   12...Ng4 13.Nxc7+ Kd7 14.Qxa7 ) 11.Kb1 Qc5 12.Nf3 ) 7.Qf2 e5


Black can also decline the pawn with 5...c6 or 5...e6, holding the position. 

O'Kelly Defence

1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 c6 This is a way to transpose to the Ziegler Defence without allowing the 6.Bd3 option  5.Bc4 Other bishop moves allow Black to achieve superior versions of standard BDG variations (5.Nxe4 is a transposition into a harmless sideline in the Fantasy Variation of the Caro-Kann 1.e4 c6 2.d4 d5 3.f3 Nf6 4.Nc3 dxe4 5.Nxe4 ) (5.fxe4 e5! is good for Black ) 5...exf3 (5...b5!? 6.Bb3 e6 has independent significance, see Short-Bareev ) 6.Nxf3 Bf5 is a transposition into the main line of the Ziegler Defence 

The only game I could find by a GM playing the BDG used this line. Nigel Short has beaten 12 world chess champions, but could not beat Evgeny Bareev.

Short, Nigel D - Bareev, Evgeny Sarajevo Bosnia 30th 2000

1.e4 c6 2.Nc3 d5 3.d4 dxe4 4.Bc4 Nf6 5.f3 The O'Kelly variation of the BDG by transposition.  5...b5!? 6.Bb3 e6 7.fxe4 b4 8.Nce2 Nxe4 9.Nf3 Ba6 10.O-O Bd6 11.c4 bxc3 12.bxc3 Nd7 13.Qc2 Nef6 14.c4 O-O

Moves are clickable

Black is a safe pawn up. White finds it hard to get adequate compensation.  15.c5 Bc7 16.Bg5 h6 17.Bh4 Qc8 18.Rfe1 Bxe2 19.Rxe2 Nd5 20.Rf1 Qa6 Stockfish gives this as =  21.Re4 Rae8 22.Rfe1 N7f6 23.Bxf6 Nxf6 24.Rh4 Qa5 25.Re2 Re7 26.g3 Rb8 27.Kg2 Rbe8 28.Qd3 Nd5 29.Ne5 Qc3 30.Qxc3 Nxc3 31.Rd2 Bxe5 32.dxe5 Nd5 33.Ra4 Rb8 34.Ra5 Kf8 35.Kf3 Reb7 36.h4 Ke7 37.Rd4 f6 38.exf6+ gxf6 39.Rda4 Nc3 40.Ra3 Nb5 41.R3a4 Rd7 42.Bc4 Nc3 43.Ra3 Nb1 44.R3a4 Nd2+ White is struggling badly from here on.  45.Ke3 Rg8 46.Be2 Rxg3+ 47.Kf2 Rc3 48.Rxa7 Ne4+ 49.Kg2 Nxc5 50.Rxd7+ Kxd7 51.Ra7+ Kd6 52.a4 Rc2 53.Kf1 Ke5 54.a5 Kf4 55.Rg7 Ne4 56.Bd3 Ra2 57.a6 Nd2+ 58.Kf2 Nf3+ 59.Be2 Nd4 60.Rg4+ Ke5 0-1

Vienna Defence

1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 Bf5 This is considered by some to refute the BDG. White can play for compensation for a pawn with  5.fxe4 ( Alternatively 5.g4 aims to regain the pawn in most cases, e.g. after  5...Bg6 6.g5 (6.h4!? is a gambit option, which leads to sharp play and approximately equal chances. ) 6...Nd5 7.Nxe4 Nc6 8.Bb5 e6 9.Bxc6+ bxc6 10.Ne2 c5 11.dxc5 Nb4

Moves are clickable

when in a reversal of roles, White has an extra pawn but Black has a superior pawn structure plus the initiative. ) 5...Nxe4 6.Qf3 when both 6... Nxc3 and 6...Nd6 lead to complicated positions in which Black often tries to return a pawn on b7 in order to catch up on development, and in some cases secure a positional advantage. White often does best to continue with a gambit policy and simply continue developing. The main line runs  6...Nd6 7.Bf4 e6 8.O-O-O Here  8...c6 9.g4 Bg6 10.Qe3 Be7 when Black is solid, but White retains enough compensation for the pawn. For example Lynn-Sutton below 

Lynn, William - Sutton, Richard New Zealand Championship 1971

1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 Bf5 5.fxe4 Nxe4 6.Qf3 Nd6 7.Bf4 e6 8.O-O-O c6 9.g4 Bg6 10.Qe3 Be7

Moves are clickable

11.Nf3 O-O 12.Ne5 Kh8? (12...Nd7 ) 13.h4 Offering a second pawn.  13...h5 14.Nxg6+ fxg6 15.Bd3 hxg4 16.h5 g5


17.h6! White offers a bishop to remove Black's pawn protection from his king.  17...Nf5 18.hxg7+ Kxg7 19.Qxe6 Richard Sutton was NZ Champion in 1963, 1971 and 1972. William notes that despite this sole loss, Richard successfully defended his NZ Championship in this tournament. The game appeared in several magazines in NZ at that time including one with approving annotations by Ortvin Sarapu. The game later appeared in several books on the BDG. "A well prepared line in that I used only one minute on the clock up to move 11 but several more minutes after that..." ( If 19.Qxe6 Rf6 20.Be5 ) ( If 19.Qxe6 Qd7 20.Be5+ ) ( If 19.Qxe6 gxf4 20.Bxf5 ) ( Or if 19.Qxe6 Nd7 20.Bxf5 ) 1-0

Langeheinicke Defence

1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 e3

Moves are clickable

This is sometimes used by strong players to avoid complications, but it is one of Black's weaker options against the BDG as returning the pawn in this way does not significantly slow down White's initiative, and thus Black struggles to fully equalize in this line. In most lines White must seek to place a knight on f4 (taking the sting out of ...Nd5) in order to secure an advantage. 

Lemberger Counter-Gambit

1.d4 d5 2.e4 dxe4 3.Nc3 e5 This is an alternative, where Black counterattacks against the d4-pawn instead of defending the attacked e4-pawn. Ed: I am reminded of John Cox's humorous comments in his book 'Dealing with d4 Deviations'. "For some reason the BDG attracts the most fanatical followers of any opening, bar none. If you've ever felt that wounded tigresses can be a little overprotective of their cubs, hop over to one of the numerous BDG websites and venture the view that you've always wondered whether perhaps the gambit is unsound and that maybe the Catalan is a better bet for long-term pressure." I must give Nigel credit for being pretty even-handed and not making unrealistic claims about the objective merit of the opening! Incidentally this variation is Cox's recommendation for defusing the BDG. He introduces his argument as follows "This goes by the marvellous name of the Lemberger Counter-Gambit (although in fact Black isn't gambitting anything)." Cox also observes that the BDG abounds as no other opening in exotic and obscure names for its variations, something that readers of this article have probably noticed as well!  4.Nxe4 Is one way of keeping a lively and complicated position ( Unconvincing is 4.Qh5 Nc6! ) ( Similarly 4.Nge2 Nc6! ) (  It's possible to accept a drawish endgame with 4.dxe5 Qxd1+ 5.Kxd1 ( or 5.Nxd1 Nc6 6.Bf4

Moves are clickable

) 5...Nc6 6.Nxe4 Nxe5 with equality and few winning chances for either side. ) ( For 4.Be3 see next game ) 4...Qxd4 5.Bd3 ( or 5.Qe2 with complications and some compensation for the pawn in either case, but it is unclear if it is enough. )

William Lynn - Rong Wang NZ Rapid Championship 2001 2001

1.d4 d5 2.e4 dxe4 3.Nc3 e5 4.Be3 Avoiding the exchange of queens  4...exd4 5.Bxd4 Nc6 6.Bb5 Qg5 7.Nge2 Qxg2 8.Rg1 Qxh2 9.Qd2 Bd7 10.O-O-O O-O-O 11.Nxe4 f6? This weak move shifted the initiative to White. Better was Nge7.  12.Bxa7 Nxa7 13.Bxd7+ Kb8 14.Qa5 Qe5 15.Qxe5 fxe5 16.Ng5

Moves are clickable

16...Nf6? This blunder loses the exchange. Bd6 holds the position.  17.Nf7 Rxd7 18.Rxd7 Nxd7 19.Nxh8 and White went on to win in 42 moves. Bravo William! 1-0

The natural looking 3...Bf5 is well met by 4.f3, and if 4...exf3 then 5.Qxf3 attacking the bishop. See how William deals with this:

Lynn, William - Hunt, Simon Hamilton CC Chp 1992

1.d4 d5 2.e4 dxe4 3.Nc3 Bf5 There is no name for this variation as this is considered an inferior move.  4.f3 exf3 ( Black may be better off transposing to the Vienna Defence with 4...Nf6 ) 5.Qxf3 Qc8 6.Bc4 Be6 7.Bxe6 Qxe6+ 8.Nge2 c6 9.O-O Nf6 10.Nf4 Qd6

Moves are clickable

11.d5 This opens lines for White's pieces.  11...g6 12.Be3 Bg7 13.dxc6 bxc6 14.Rad1 Qb4 15.Ncd5


15...cxd5? (15...Qb7 is about equal.  ) 16.Nxd5 Qa5 17.Bb6! The winning move.  17...Qxa2 18.Nc7+ Kf8 19.Rd8+ Ne8 20.Rxe8# 1-0

Sometimes your opponent will avoid the BDG and turn it into a French defence by 1... e6, or Caro-Kann by 1... c6. But William was well prepared for that in the following game. (Ed: These options must be a real buzzkill for BDG fanatics. Perhaps I could recommend Scott Wastney's 3. Bd3 article in this very issue as a way to often get a lively open game with attacking chances, against the French option at least).

Lynn, William - Waayman, Roel North Island Championship 1970

1.d4 d5 2.e4 e6 3.e5 c5 4.c3 Nc6 5.Nf3 Qb6 6.Bd3 cxd4 7.cxd4 Bd7 8.O-O Nxd4 9.Nxd4 Qxd4 10.Nc3 a6 11.Qe2 Ne7 12.Rd1 Qb6 13.Be3 Qd8 (13...Qc7 is better ) 14.f4 g6 (14...Rc8 is better ) 15.Rac1 Nf5? Stockfish still gives Black 0.4 lead after Bg7.  16.Bxf5 gxf5

Moves are clickable

17.Rxd5 William notes, "The rook sacrifice (Stockfish +0.5) was only decided after looking at Nxd5 (+2.2) first, but I could not find a suitable followup. Rxd5 was based on superior development and an intuitive assessment of the attacking possibilities, and I wanted to prevent Black from castling, so that mating ideas could develop."  17...exd5 18.Nxd5 Rc8? Stockfish gives Be7 or Bg7 as =  19.Nf6+ Ke7 20.Rd1 Rc7 21.Qd2 Qc8 22.Bb6 Rc6 23.Qb4+ Ke6 24.Qb3+ Rc4


25.Nxd7 Ke7 26.Qa3+ White mates in 6 or fewer moves whatever Black plays. William was given the nick-name "Wild Bill" for a few years after this game. 1-0


The BDG is "coffee house chess" according to Michael Steadman, and the fact that I could not find a single game played by two titled players lends support this assessment. However, there are so many rich possibilities, plus the surprise factor, that makes it well worth trying.