Returning to the theme of forgotten variations, another line that few people play these days is the Swedish Variation of the Tarrasch Defence (1. d4 e6 2. c4 d5 3. Nc3 c5 4. cxd5 exd5 5. Nf3 Nc6 6. g3 c4). Actually it has never been played that much, though it was a firm favorite of the Swedish Grandmasters Gideon Stahlberg and Goesta Stoltz.
The idea behind 6…c4 is that Black sets up a queenside pawn majority and avoids the isolation of his d-pawn via a White dxc5. On the other hand it gives White a free hand to play e2-e4, which is supposed to be the great drawback. But this too is not so clear, for example a game Reinderman – Akobian, Wijk aan Zee 2010 showed an interesting approach for Black with 6… c4 7. Bg2 Bb4 8. O-O Nge7 9. e4 Bxc3!? (almost never played) 10. bxc3 O-O 11. Ng5 h6 12. exd5 Nxd5 13. Qf3 Nf6 14. Ne4 Nxe4 15. Qxe4 Re8 16. Qf4 Be6 17. Rb1 Qd7, with a very reasonable game for Black.
On the other hand the element of surprise can be quite dramatic, especially against players prone to getting into time trouble. And that might explain how six time US champion Walter Browne got into such trouble against Smbat Lputian: