In my post Great improvement in the Teichmann defense I discussed black's defense after 1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Nxf3 Bg4 6.h3 Bh5 7.g4 Bg6 8.Ne5 e6 9.Qf3 c6 10.g5. I indicated that 10...Nh5 was black's best move, after which white should respond 11.Bd3.
In the earlier post, I discussed black's strongest move 11...Qxd4 with very complicated play for both players.
Now there is also 11...Nd7 12.Nxg6 hxg6 13.Rf1 Qe7 ( diagram ) that I covered in my book.
In my book I suggested 14.Be3, but now I realise that this brings nothing after 14...000 as both 15.Qxf7 Ng3 16.Qxe7 Bxe7 17.Rf7 Bd6 and 15.000 Qe8 give only equality.
The alternative 14.Bd2 is a far better try and gives white the advantage.
a/ 14...000 15.Qxf7
...a1/ 15...e5 16.Bxg6 (+=)
...a2/ 15...Ng3 16.Qxe7 Bxe7 17.Rf7 (+=)
...a3/ 15...c5 16.Qxe7 Bxe7 17.Rf7 (+=)
...a4/ 15...Qxf7 16.Rxf7 (+=)
b/ 14...Nb6 15.000 (+=)
c/ 14...e5 15.000 (+=)
Believe it or not, it really depends on details whether or not your Blackmar Diemer tries are successful.