The Benko Gambit (also known as the Volga Gambit) starts with moves 1. d4 Nf6 2. c4 c5 3. d5 b5!? Black sacrifices a pawn in order to open the a and b files, get quick development and a strong fianchettoed bishop on the h8-a1 diagonal.
The Benko Gambit is one of the most daring systems, as Black gives up the pawn from the very beginning and continues playing the game in a very ordinary way as though nothing happened. Black gets long-term initiative and keeps pressure on the queenside even if the queens are gone from the board.
There are no direct or forced ways to refute the Benko Gambit, therefore this super-agressive opening offers very complex play and remains in the repertoire of the top players. It is a little hard to use the Benko system as a regular playing setup with Black, but it may be very effective as an alternative system or for situations when we need to win at any price. The Benko Gambit has been practiced such strong players such as Carlsen, Kasparov, Anand, Topalov, Ivanchuk, Adams, Shirov, and Bareev.
To learn more about this opening setup, I definitely recommend you watch the DVD BATTLING THE BENKO: THE FIANCHETTO VARIATION – GM DAMIAN LEMOS.
The Benko Gambit Declined
White may decline Black’s pawn sacrifice on the 4th or 5th move. For instance, after 3… b5 4 .cxb5 (simply 4. Nf3 is also possible) a6 White can avoid Gambit lines by playing 5. b6!? This kind of reaction is called The Benko Gambit Declined.
In this case, we often get some hybrid structures of the Indo-Benoni system that is shown on the diagram. Obviously, Black is going to take the b6 pawn on the next move. The a1-a8 vertical is already closed, but Black still pressures on the b file and a1-h8 diagonal. He is also looking forward towards the Ne8-c7 maneuvering idea that may be continued with f7-f5 or e7-e6 strikes, or simply with the transfer of the knight on the b5 square (later possibly on d4 too). Nowadays the declined Benko Gambit is absolutely a playable line for Black, with a lot of dynamic possibilities and practical chances.
The Benko Gambit Accepted
The Benko Gambit Accepted variation is the critical line and principal test for the whole playing setup. White has few sub-lines, but a fianchetto system is played most often.
We see this position from the game Johannessen – Carlsen, played in 2006. Black placed his pieces logicaly and now Carlsen makes a typical maneuver Ng4-e5. 13… Ng4!? 14.Bd2 Nge5 15.Nxe5 Nxe5 16.b3 White always tries to find such a position for the queenside pawns, in which they will be under less pressure, but it is not easy as Black is pressuring on both semi-open files. 16… Bc8!?
Now Carlsen demonstrates another famous idea by transferring the bishop on f5 in order to provoke the e2-e4 move. It would weaken the d3 square and the black bishop can return to a6. Furthermore, Black always has to remember about the c5-c4 strike that could increase the activity of his pieces.
The game continued with 17.Na4?! Qa6 18.Bc3 Bf5! 19.Be4 Bd7! 20.f4 Ng4 (20… Bxa4 also deserved serious attention) 21.Bxg7 Kxg7 22.Nf3 c4! and Black got a great position, which ultimately led to a win for Carlsen.
WATCH THESE VIDEOS FOR MORE INFO ON THE BENKO GAMBIT: