Actions taken to determine if one is under surveillance. For example, a driver must make a sudden U-turn to see if a following car does the same. In sophisticated surveillance practices, such dry cleaning is expected. A subject may, for example, be followed by several cars on parallel routes. The U-turn would be picked up by a second car.

Midway

The "turning point" of World War II in the Pacific occurred when an inferior U.S. naval force decisively defeated a Japanese fleet attempting to capture Midway Island in the Hawaiian Islands and force the U.S. fleet into decisive battle. The American victory at Midway was possible because U.S. Navy cryptologists were able to read the Japanese naval code.