Zepler doubling refers to a specific tactic employed in chess problems. It involves a piece initially moving along a particular line, such as a rank, file, or diagonal. Subsequently, another friendly piece enters the same line, followed by the first piece resuming its movement in the same direction as previously. This maneuver is exclusive to the realm of chess problems.
Erich Ernst Zepler, the author of this concept, was a German-born electronics expert, lecturer, and chess problem composer. He created the original problem in 1929:
While the Zepler doubling tactic is commonly associated with chess problems, it is worth noting that it occasionally emerges in actual chess games too, albeit rarely. In an upcoming article, we plan to delve into an analysis of a renowned game between Rubinstein and Hromádka, which notably showcased the employment of the Zepler doubling pattern.