Hi.
Michael Ayton wrote on 06/27/17 at 09:29:39:
Many thanks for all this hard work, C_b_T! I regret I haven't had time lately to look at things closely, but one evening a week or two ago I was doing what you're not meant to do, namely just running an engine and watching passively, and it came up with something I thought quite interesting after 12 Bf6 ef 13 Nf3 in the line above, namely 13 ...a5!?. The idea I guess is to delay ...Be6 for the moment and to enable a possible ...Ra7. The sequel was fascinating!: 14 Re1 f5 15 h4 (15 Rg1?! Nd7) h5 16 Ng5 Ra7 17 Rh3 Ba6 18 Rg3 Bf1, and now came a wild attack! -- 19 d5!? Re8 20 Ne6! fe 21 Rg6 ...
Looking at this again very quickly I have no idea whether Black can defend or not. Maybe he can, but it sure looks dangerous, and I take your point about White having other options anyway. All in all, maybe Black should grit his teeth and accede to the tedious endgame line after all ...
I'm not sure about some of those moves. White's strategy seemed a bit based on that carneval games where you have to throw and knock down an entire pyramid of cans with a set number of balls. It felt like the attempts kept coming at fast pace without any finesse and in the end position I think black is going to hold and probbably without problems if white does not have some nice idea.
Since I brought up the subject of finesse, maybe white can consider 13...a5 14.h3!? to prepare g4+Bg2 and give black a less secure structure in the long term (13.h3 sort of comes to mind as well even if looks like a less good version).
Have a nice day.
Edit:
General observations on 4.Bg5 lines... If white plays the absolute best lines with some accuracy I don't think the picture looks great.
Ideally I would like 1
.e4 d6 2.d4 Nf6 3.Nc3 g6 4.Bg5 Bg7 5.Qd2 h6 6.Bh4 0-0 7.0-0-0 c6 8.f4 b5 9.e5 dxe5 to work. Although as I mentioned white has 10.dxe5 and the f4+e5 wedge is not fun to meet.
Then there is
1.e4 d6 2.d4 Nf6 3.Nc3 g6 4.Bg5 Bg7 5.Qd2 h6 6.Bh4 0-0 7.0-0-0 c6 8.f4 b5 9.e5 b4 although in this you need to degrade your structure and play fairly prospectless positions, which even though white has no immediate breakthroughs look not really trustworthy imo.
If all else there is this endgame line with
1.e4 d6 2.d4 Nf6 3.Nc3 g6 4.Bg5 Bg7 5.Qd2 c6 6.Bh6 Bxh6 7.Qxh6 and yea... 7...Qa5 or 7...e5. I am fairly certain these are not the lines of the future though.
I have come to the conclusion that I will just give up on 4.Bg5 Bg7 for now and try 4...c6 5.Qd2 Nbd7 next time I face 4.Bg5. If nothing else it's a line that needs proving in practice (and also probably a bit more proof of concept analysis as well...

)