Geller's System

Geller's System is White's quiet way of exploiting Black's delayed ...Nf6 in the Modern Defense. Instead of developing the queen's knight, White plays 4. c3. This backs up the d4-pawn and takes the sting out of the long diagonal, so the g7-bishop meets a firm pawn chain rather than a target. The price is that White's queen's knight gives up c3, and the system is slower than plans such as the Pseudo-Austrian Attack. The same position can come from 3. c3 followed by 4. Nf3. It is classified under B07.

Black's most common reply, by a wide margin, is 4...Nf6. Attacking e4 at last leads to a Pirc-type game in which White already has a solid center. The alternatives are 4...Nd7 and 4...Nc6, each seen in a little over a tenth of games. Both keep the knight flexible and prepare to challenge the center with ...e5. Engines also suggest the queenside move 4...a5. They give White a slight edge, but in online play Black scores marginally better than White.