United States color-coded war plans

During the 1920s and 1930s, the United States military Joint Army and Navy Board developed a number of color-coded war plans to outline potential U.S. strategies for a variety of hypothetical war scenarios. The plans, developed by the Joint Planning Committee (which later became the Joint Chiefs of Staff), were officially withdrawn in 1939 in favor of five Rainbow Plans developed to meet the threat of a two-ocean war against multiple enemies.

Colors

The use of colors for U.S. war planning originated from the desire for the Army and Navy to use the same symbols for their plans. At the end of 1904, the Joint Board adopted a system of colors, symbols, and abbreviated names to represent countries. Many war plans became known by the color of the country to which they were related, a convention that lasted through World War II. As the convention of using colors took root, some were eventually reused, such as Grey, which originally referred to Italy but eventually became a plan for the capture and occupation of the Azores.