Refuted for the wrong reason

Several “experts” have refuted the Blackmar Diemer gambit based on the Ziegler position. Traditionally, white attacked like a berserker in the line 1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 c6 5.Bc4 exf3 6.Nxf3 Bf5 7.Ne5 ( better is 7.Bg5 ) e6 8.00 Bg6 and now the berserk move 9.g4 (?!).

Unfortunately, white’s last move does not attack anything and black has time to challenge the white knight. This can be done in two ways : 9…Nbd7 and 9…Bd6. The critics have suggested 9…Nbd7 to prove that the Blackmar Diemer gambit is refuted. But is this line really that bad ? White certainly has nothing else but 10.Nxg6 hxg6 11.g5 (diagram)

Let's look at this position now :

a/ 11…Qc7 (the “refutation” appears) 12.Qe2 (diagram)

…a1/ 12…Bd6 13.Rf2

……a1a/ 13…Nd5 14.Bxd5 cxd5 15.Nxd5 (=)

……a1b/ 13…Nh5 14.Ne4 (=)

……a1c/ 13…Nh7 14.Ne4 (=)

……a1d/ 13…Ng8 14.Rxf7 (=)

……a1e/ 13…Rh4 14.gxf6 Nxf6 15.Bg5 (=)

…a2/ 12…Nd5 13.Bxd5 cxd5 14.Nxd5 (=)

…a3/ 12…Nh5 13.Rxf7 (+=)

…a4/ 12…Ng8 13.Rxf7 (+)

…a5/ 12…Nb6 13.Bxe6 fxe6 14.gxf6 (+=)

…a6/ 12…000 13.gxf6 Nxf6 14.Bf4 Bd6 15.Bxd6 Qxd6 16.Rad1 (=)

b/ 11…Nd5 12.Qf3

…b1/ 12…f5 13.gxf6 (=)

…b2/ 12…f6 13.Re1 (=)

…b3/ 12…Qe7 13.Nxd5 (=)

c/ 11…Nh5 12.Qf3 (+=)

d/ 11…Nh7 12.Qg4 (=)

e/ 11…Nb6 12.Bxe6 fxe6 13.gxf6 gxf6 14.Qg4 (diagram)

…e1/ 14…Kd7 15.Qxg6 (=+)

…e2/ 14…Kf7 15.Bg5 (=)

…e3/ 14…f5 15.Qxg6+ Kd7 16.Rf3 (=+)

…e4/ 14…Bg7 15.Qxg6+ Kf8 16.Ne4 (+=)

…e5/ 14…Be7 15.Qxe6 (=+)

To be noted is that black can also challenge the white knight by means of 9…Bd6, but that is a different story.

So it seems white has indeed a difficult time in the Ziegler position, but not because of the so called “refutation” 11…Qc7, but rather because of 11…Nb6 ( or 9…Bd6 ) Fortunately, the resulting position is really complicated and a well prepared attacker can emerge with an even game. But chances seem very small that your opponent will find this single continuation in an over-the-board game, with the clock ticking away.