An interesting Lemberger

First of all, let me apologise for not posting so long - sometimes other things n life such as work get priority. I know, it is a false excuse for not playing chess , but still...

Yesterday evening I started a knockout tournament where the lower rated player advances to the next round in case of a draw. I was lucky twice - I am the lower rated player and I was playing white.

My opponent choose the Lemberger defense, but I got a crushing attack.

Guido De Bouver - Jan Jelgrims.
Mechelen 2015
1.d4 d5 2.e4 dxe4 3.Nc3 e5
the Lemberger. Good for balck, but certainly no refutation.

4.Nxe4 Qxd4 5.Bd3 (diagram)

5...f5 is the most crushing move by black here, also suggested by Diemer.

5...Nc6 6.Nf3 Qb4+ 7.c3 Qe7 8.0-0 f5 (diagram)
Better late than never, as the saying goes.

9.Ng3 g6
My opponent aims to defense his centre from behind with a bishop on g7.
However, my position is great position and I should have difficulties in finding a bad move.

10.Qb3
I found it !!

10...Bd7
Luckily, my opponent also misses the chance to equalize.

11.Bg5
A key move. I open up the 1st rank for my rooks and bring the knight to f6 - limiting the scope of the future bishop on g7.

11....Qc5 12.Be3 Qe7 13.Bg5 Nf6
I was happy to repeat moves as I would advance into the next round after a draw.
Now, with the first rank cleared for my rooks, I decided it was time for a sacrifice

14.Nxe5 (diagram)

14...Nxe5 15.Qxb7 Bc6
Both 15...Rc8 and 15...Rd8 would have been a bit better

16.Bb5 Bxb5 17.Qxa8+ Kf7 18.Bxf6
I was under the impression I had a better position, but since a draw was suffcicent, I wanted to exchange a few pieces. Unfortunately, this exchange gives black the better play.

18...Kxf6 19.Rfe1 (diagram)

Black now misses a simple move to lock my queen away : 19...c6 would have been quite effecitive !

19...Qc5  20.Qd8+ Kg7 21.Qd2 bd6 22.b4 Qc6 23.Qd4 (diagram)

Draw agreed here. Black cant avoid exchanging queens after which I will be a pawn up - hopeless situation for black as he needs to win to advance.

A potential line could be :
23...Qb6 24.Rxe5 Qxd4 25.cxd4 Bxe5 26.dxe5 and white is a pawn up.

So it is clear that the Lemberger is not the ultimate refutation against the Blackmar Diemer as the resulting positions are very complicated ( maybe more complicated than the main lines ).