London System vs. the Benoni: 3. d5
"Autumnal London" by Veronika Benoni

London System vs. the Benoni: 3. d5

IndreRe
IndreRe
Jul 4, 2018, 9:40 PM |
7

Last week we started looking at how White can respond to the Benoni move 1. d4, Nf6 2. Bf4, c5 with 3. e3 and 3. dxe5. This week I'll look at the main recommendation, 3. d5, and try to come to some conclusions (at least for myself) as to which is the most practical repertoire choice.

3. d5 - the Advance

Black can meet the advance with the thematic 3...Qb6, the Benkoish 3...b5, or the simple 3...d6, followed by either ...e5 or ...g6:

Let's look at each in more depth.
3.I - the Thematic 3...Qb6
Black can follow up 3...Qb6 with grabbing the pawn, which transposes to a line of the Trompowsky called the Vaganian Gambit. This one is good for White:
Here's the classic miniature by Vaganian:
A much more testing option is 3...e6 and here White needs to know his stuff. The following analysis is by GM Simon Williams:
3.II - the Benkoish 3...b5!?
Black can try the Benkoish 3...b5 and this can get tricky very fast:
Here's Carlsen beating Ivancuk in this line:
3.III - the Simple 3...d6
Finally, Black can play the simple 3...d6, followed up by either ...e5 or ...g6. I'm not sure this gives White any advantage either:
Here's Grischuk vs Gelfand in one of these lines:
Conclusion
So which line is the most practical repertoire choice? Well, I think the only two serious options are 3. e3 or 3. d5 with 3. dxc5 being at best a surprise weapon.
3. e3:
In favor of 3. e3, you keep the game in familiar London waters, and if Black doesn't react critically with 3...Qb6, it might just transpose to some other line. The critical line allows White to either take the draw  (which is not a bad option against stronger players) or three different ways to play on in an active, if very messy, middlegame, with "chances for both sides".
3. d5:
In favor of 3. d5, you might get a theoretical advantage on paper. From a learning perspective, you get to play a different sort of structure, which is important for one's development as a player. However, there are many different lines (or types of positions) to learn and many of them are quite messy as well (3...b5!?) while some seem to be nothing more than just equal (e. g. 3...d6 followed by ...e5).
In sum:
At the non-GM level, I think 3. e3 shouldn't be discounted at all, no matter the common lore. However, it is best to probably play both over time and see how you like the resulting positions. If you play it OTB and can prepare for your opponent then of course you could try varying depending on whether they're normally a Benoni player or not.
Enjoy!
Indrek