Stockholm Variation

The Stockholm Variation meets the Grünfeld with 4. Bg5. White develops the queen's bishop actively instead of exchanging on d5 at once or committing to 4. Nf3. The bishop targets the f6-knight, the piece that guards d5 and keeps e4 under control, so a later Bxf6 can weaken Black's hold on the center. White avoids the large pawn center of the Exchange Variation and its forcing theory. As a result the variation is usually described as the most positional of the main fourth-move tries.

Black has three common replies. The most popular is 4...Bg7, which completes the fianchetto and allows the bishop to recapture if White exchanges on f6. Next comes 4...Ne4, which attacks the bishop at once and offers to trade the knight on c3 or e4. In Lichess games it has given Black the best results of the three. The quieter 4...c6 supports d5 with a pawn and produces a Slav-like structure. The engine rates the position as roughly balanced, and online results are almost exactly even. The line appears far less often than the Exchange or Three Knights systems.