Game of the Month
Pawn Power
The Modern Benoni affords an illustration of what Hans Kmoch
referred to as "levers" in his classic book "Pawn Power in Chess" -
White tries to get in the move e4-e5, rolling up the center before
Black is able to knock White off his formation with the queenside
counterattack ... b5-b4. Such was the issue in the game between Jaan
Ehlvest and Nick deFirmian from the 1997 New York Open.
Ehlvest decided to stake all his marbles on the e4-e5 break,
dispensing with precautionary maneuvers on the queenside. As it turned
out, Ehlvest did get there first - but deFirmian's lever came with
more force.
Ehlvest,Jaan (2635) - de Firmian,Nick (2575) [A75]
NY Open (6), 1997
1.d4 Nf6 2.c4 e6 3.Nf3 c5
deFirmian is one of many GMs who play the Benoni only in response
to White's Ng1-f3 so that the Four Pawns Attack will not have to be
faced. For example, had White played 3 Nc3, then on 3 ... c5 White
can play 4 d5 exd5 5 cxd5 d6 6 e4 g6 7 f4. Thus, a good repertoire
is to combine the Nimzo-Indian (if 3 Nc3 Bb4) with the Benoni (if 3
Nf3 c5).
4.d5 exd5 5.cxd5 d6 6.Nc3 g6 7.e4 a6 8.a4 Bg4 9.Be2 Bxf3
Preferring to avoid the variation where White preserves his
knight with the maneuver Nf3-d2, after, for example, 9 ... Bg7 10 Bf4
O-O 11 O-O Qe7 12 Nd2 Bxe2 12 Qxe2 and the d2 knight is headed to c4.
10.Bxf3 Nbd7 11.0-0 Bg7 12.Bf4
An interesting approach to the position was taken in Grivas -
Minasian, Debrecen 1992, where White anticipated the arrival of a Black
knight on e5 by playing 12 Be2!? O-O 13 Re1 Re8 14 Bf1. Because White
has never posted his dark-squared bishop on f4, he is ready to meet ...
Nd7-e5 with an immediate f2-f4.
Qe7 13.Re1 0-0
DIAGRAM
14.Qd2
Ehlvest diverges from 14 a5, which he used to defeat Minasian at
the 1993 New York Open. Although 14 a5 allows Black to open the b-file
quicker (as White could prevent the file-opening by leaving the pawn
on a4 and controlling the b5 square), it also threatens to create
favorable queenside activity with Nc3-a4, forcing the issue. Minasian
tried 14 ... Ne8?! 15.Na4 Nc7 16.Bg4 Ne5 17.Nb6 Rad8 18.Bh3 Na8
19.Bxe5 Bxe5 20.Nc4 and White had an edge. Spurred on by that success,
Ehlvest again essayed 14 a5 against Kovacevic at the 1994 Linares
Open. There Black obtained sufficient b-file counterplay with 14 ...
Rab8 15.Qc2 b5 16.axb6 Rxb6 17.Na4 Rb4 18.Bd2 Rb7 19.Nc3 Rfb8. And in
Barlov - deFirmian, Novi Sad (Ol.) 1990, deFirmian succeeded using
kingside activity after 14 ... Ne5 15.Be2 Rfe8 16.Bg3 g5! 17.Ra4 Nfd7
18.Bf1 Ng6 19.Re3 Rac8 20.h3 Nde5 with a very sharp position. It is
likely that Ehlvest was familiar with the Barlov game, as his 14 Qd2
acts to prevent Black from establishing the formation with ... g6-g5.
Rfe8 15.h3 Ne5 16.Be2 Qc7
DIAGRAM
17.Bh2
Committing to a breakthrough with f2-f4 and e4-e5. A very different
idea was 17 b3!?, in order to meet 17 ... c4?! with 18 b4!,
effectively closing down Black's queenside play. Instead, Black should
play 17 ... Qa5 with an unclear situation.
c4 18.Kh1 Rab8 19.f4
Consistent. White's b-pawn would be too weak after 19 a5 b5 20 axb6
Rxb6! (better than 20 ... Qxb6 21 f4 Ned7 22 Bxc4).
Ned7 20.Bf3 b5 21.axb5 axb5 22.Ra6
The main object of this incursion is to create enough of a
distraction to Black's pieces to get e4-e5 in.
DIAGRAM
Nc5!
Also possible was 22 ... b4 giving White the opportunity of 23 Na4,
trying to restrict the Black knight on d7. Then 23 ... Qb7! 24 Rxd6
Qb5 leads to frightful complications after, for example, 25 b3 cxb3 26
Nb2 Rac8 27 e5.
23.Rc6 Qa5 24.e5
White has to get on with the program. There is no stopping Black
from creating havoc on the queenside.
Nd3 25.Re2
DIAGRAM
b4!
A critical, and typical move. Often, in Benoni, King's Indian and
Pirc positions, e4-e5 by White must be answered by ... b5-b4 by
Black; otherwise, White's c3 knight becomes too strong in the center.
In this case, if 25 ... dxe5 26 fxe5 Nd7 27 e6 N7e5 28 exf7+ Kxf7 29
Re6 would be strong for White, as the c3 knight will come into play
via e4.
26.Nd1
White's center would be dissipated, and his position disorganized,
after 26 exf6 bxc3 27 bxc3 Bxf6.
dxe5 27.fxe5 Nd7 28.e6
A defensive-minded player might try 28 Rxc4 N3xe5 29 Re4,
minimizing the damage to the edge which Black's strong knight on e5
confers, but it is extremely difficult to switch to such a mode.
N7e5
DIAGRAM
29.Rxc4
A reasonable-looking exchange sacrifice, to try to do away with
the twin threats of ... Ne5xc6 and ... Ne5xf3 followed by ... Qa5xd5.
Ehlvest avoids the immediate 29 exf7+ as this may only strengthen the
position of the Black knight on e5 after 29 ... Kxf7.
fxe6!
An important interpolation. White would be happy enough after 29
... Nxc4 30 Qxd3. But now if White runs with his rook, then the
center is completely demolished after exd5.
30.dxe6 Nxc4 31.Qxd3 Rbd8
The suddenly open d-file allows Black to assume the initiative.
32.Qxc4 Rxd1+ 33.Bg1 Qa7
The Exchange up, deFirmian pursues a policy of ruthless
simplification.
34.e7+ Kh8 35.Rf2 Rxg1+ 36.Kxg1 Bd4 37.Qf7 Qxe7 38.Qxe7 Rxe7 39.Kf1
Bxf2 40.Kxf2 g5
0-1