Schallopp Defense

Named after the 19th-century German master Emil Schallopp, 3...Nf6 develops a piece and attacks e4 rather than supporting the f4-pawn with ...g5. The usual reply, 4. e5, gains space and drives the knight to h5, where it guards f4. Black then aims for ...d5 to close the center, or ...d6 so that exd6 lets the bishop recapture on d6. Black often adds ...g5 afterward, reaching it by a route that sidesteps the standard attacking setups. The h5-knight is undefended, which leaves tactics: after 5. d4 d6 6. Qe2, 6...Be7 loses a piece to 7. exd6 Qxd6 8. Qb5+, whereas 6...d5 holds. The sharpest attempt, 5. g4, is the Tashkent Attack.

Nearly as popular is 4. Nc3, which protects e4. Black usually strikes with 4...d5, and then 5. e5 Nh5 or 5...Ne4 follow, while 5. exd5 transposes to the Abbazia Defense. 4. Bc4 is also seen. Interest grew in the 21st century, notably after Ding Liren used the line to beat Magnus Carlsen in the 2020 Magnus Carlsen Invitational. Engines slightly favor Black, but White scores better in online games.