The beginning of 1920 saw Rubinstein engaged in a difficult match with Bogoljubow. The split-venue battle, divided between the principal Swedish cities of Stockholm and Gothenburg, looked to be a runaway when Rubinstein won the first two games, but then Bogoljubow found Akiba's Achilles' Heel - his pet 4...Nd4 in the Four Knights Game. Bogo scored a perfect 3 for 3 as White in this opening, but declined to try it a fourth time in the crucial 11th game. Instead, he used the Ruy Lopez and Rubinstein won after a hard fight. A draw with White in the last game kept Rubinstein's remarkable undefeated match record intact.