As the three-to-one rule of thumb appears to have evolved out of the American Civil War (although not as published in FM 6-0), then we should probably look at just our Civil War battles in our database. Among those 243 cases are 49 cases from the American Civil War. As the three-to-one rule may have … Continue reading The U.S. Army Three-to-One Rule versus 49 U.S. Civil War battles