stockhausen wrote on 06/24/19 at 06:17:11:

Well, it is addressed again in the latest update ...

One case of ...Rxe5 in the old version which stuck in my memory was a game between Joel Lautier and Yacov Murey.  Let's just say that losing one tempo with White may not make a lot of difference, but losing two is probably not recommended ...

I'm not an avid correspondence player like Vass (but a reasonably strong OTB player) but I think overall my impression is that Black should be holding a draw reasonably comfortably with optimal play. I agree that ...f7-f5 is probably just a pipedream and at best  Black can hope for ...b7-b5 with subsequent liquidations on the queenside. Black essentially has to content himself with shuffling around pieces in a cramped position but should be okay. Therefore, in practical OTB play I'd imagine this could prove difficult for Black but from a theoretical point of view and in correspondence play, I really don't think White has much.

Maybe I will have a more in-depth look at the position at some point, and if I find any ways for Black to activate his position Ill let you know but for now White does seem to have a certain grip on the position.

That of course is also comparable to old stuff; in the version without a tempo loss by White, the ...Bh6 approach has been commonly considered +=.  In one of the first major games in the non-tempo-loss version, Kavalek even played exactly as in that van Kampen variation, with his opponent Botvinnik having the added move Rf2 at the end.  Though the game was drawn, apparently ...Ne5 was just bad in that case.

Incidentally a forthcoming pawn-structure book by GM Rios has a chapter on this general kind of thing, which he calls the Symmetric Benoni.  (I think it was called the Russian Benoni by Steffen Zeuthen, a seemingly mysterious guy who wrote some Benoni books and co-authored Zoom 001 with Larsen.)  I was hardly surprised to see that Rios uses a certain game in which Spassky managed to strangle Fischer in '92.

Vass wrote on 01/13/15 at 08:44:34:


And what do you propose after the natural 11...Bh6 12.0-0 Bxe3 13. fxe3 Qe7 14.e4 a6 15.Qd2 Ne5 16.Nxe5 Qxe5 as also suggested by Van Kampen!? This looks quite equal too me and White's advantage is symbolic if any...

Studying carefully what John Watson analyzed in his wonderful book I've won two correspondence chess games as a first player. My preferences went for 6.Bg5 in both games and my opponents played exd5, Nbd7 and Re8+ (according to standard) with a7-a6 a2-a4 included in one of these games. No matter how black twisted and turned (early b7-b5 was never played, indeed), white had a stable, though not very big advantage which I was able to turn into win:





So, it's obvious that I think 6.Bg5 is better than 6.Be3 and the loss of tempo is intentional here (white wants c7-c5 to be played) in order to receive a better pawn structure c4-d5 against c5-d6, thus gaining advantage in space. 

(Made it!) For that matter, why not (5.h3 0-0 6.Bg5 c5 7.d5 e6 8.Bd3 exd5 9.exd5) 9...Nbd7 10.Nf3 Re8+ 11.Be3 (all best play according to Watson, though 11.Kf1 "has been played exclusively here") and now 11...b5!?

In the corr. games tony37 gave, the knight goes to d7 anyway, so here ...Re8 is a free tempo, though there is the downside that Nxb5 comes with tempo on d6 (and if that is sacrificed, on e8).

Edit: Nxb5 looks effective for White in both this line and after 9...b5 (with 6.Bg5); The original Be3/Nf3 version of 9...b5 works because the bishop is not yet on d3 and 10.Nxb5 Ne4 is strong.

But 5.h3 0-0 6.Bg5 c5 7.d5 e6 8.Bd3 exd5 9.exd5 h6 10.Be3 Na6 (by analogy with tony37's 8.Bd3 line above) is still interesting. The ...h6 pawn is a slight problem for Black, but maybe he's still fine.

ErictheRed wrote on 01/12/15 at 03:24:41:

yes, but the reverse can happen too:
1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.h3 O-O 6.Bg5 c5 7.d5 e6 8.Bd3 exd5 9.exd5 Nbd7 10.Nf3 Re8+ and now best according to Watson (and I agree) is 11.Be3
which is why I thought 6.Be3 was better against 6...c5 than 6.Bg5, but 9...b5 is the spoiler for white