If we've learned anything from The Witch Who Came In From The Cold, it's the importance of guarding secrets. For much of the 20th century, particularly during the Cold War, correspondence chess, a long-distance version of the internationally-beloved game of chess, was used as a method to share—and guard—secret correspondences between nations (and their spies). During the Cold War...
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..spies in Germany sent postcards back to MI5 containing coded messages written in cryptic text based around a series of postal chess games. Gordon Thomas, historian for MI5 and MI6, said that chess moves were a common way of communicating during the Cold War. He also said the Russians in particular favored using chess as a method of communicating. It was their great national pastime and information would often be disguised as chess moves.
In a KGB handbook, a section described how to use chess moves when communicating. For example, one move could ascertain what was happening and another could give instructions. Agents would be trained to understand chess moves.
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In fact, correspondence chess had become such an effective communication method that it allowed spies to infiltrate even toughest institutions. In Washington, D.C. during the 1960s and 1970s, for example, the Soviet embassy had a resident chess expert on staff, Lev Zaitsev, who was later identified as not only a KGB agent, but a KGB colonel. It might not be magic, but it sure led to some important under-the-radar secret-sharing.
