Berlin Defense, l'Hermet Variation

The l'Hermet Variation, named after the German master and problem composer Rudolf l'Hermet, is Black's standard answer to 5. d4 in the Berlin. For the moment Black keeps the extra pawn and retreats the knight to d6, where it attacks the bishop on b5 while d4 strikes at e5. White cannot easily preserve both the bishop and the central tension, so the play quickly becomes forcing. By far the most common choice is 6. Bxc6 dxc6 7. dxe5. Now 7...Nf5 8. Qxd8+ Kxd8 reaches the Berlin Wall endgame, while 7...Ne4 is the rarer Westerinen Line.

If White allows the capture with 6. dxe5 Nxb5 7. a4 Nbd4 8. Nxd4 Nxd4 9. Qxd4 d5 10. exd6 Qxd6, the result is the well-known Berlin draw. Neither side can do better than move the queens back and forth between the d- and e-files. The retreat 6. Ba4, the Showalter Variation, lets Black choose between 6...exd4 and 6...e4, and both are judged equal. The intermezzo 6. Bg5 Be7 7. Bxe7 Qxe7 trades dark-squared bishops to delay the endgame. The engine rates the position as level, and in Lichess games Black scores better.