Ahoy!
The BDG used to be a big part of my repertoire when I used to play chess regularly over the board (@ 1800 ELO level) and I had all the books by Purser, Lane and Schiller.
To first try and answer your question, I don't know as it is not mentioned in any of the books that I have. I can only speculate that 8.Kh1 is designed to remove the king from the diagonal should Black decide on the Ng4 styled counter attack similar to Snchneider-Prins Corr 1985-86....But this is just a guess.
As for studying the BDG. I am not going to say "Don't" but the the thing is the BDG can be declined not only easily but in some cases, quite safely as well. If you are going to look at the BDG, a line against the French, The Crappo Kann and Nimzowitsch will be needed.
Happy hunting.
Hey guys,
I was just wondering if anyone could give me an explanation of this opening and as to why kh1 is played.
https://www.chess.com/openings/D00-Queens-Pawn-Opening-Blackmar-Diemer-Bogoljubov-Kloss-Attack
I'm currently looking deeply into the lines in the BDG, as I'm preparing for some club level tournaments.