By now, most people who have serve recently in the military have or at least had a challenge coin. These are generally imprinted with the branch of service on one side and the unit on the other. Given to help boost morale they have a much richer history that is up to some debate. They are often called army coins but this is simple because they are the largest branch of service and therefore the most likely to be seen. The Air Force challenge coins, however, might have been the start of their use in the US military.
That story dates back to World War I, a time before the Air Force existed by that name. Then it was known as the Army Air Corps. As the story has it, there was a early pilot that can from a family of some means. As a way of banding the other pilots together he had his family make the coins for all the pilot in his unit.
Now the story could end there and be a fine explanation to the origins of the challenge coin but it doesn’t. One of the pilots carried is coin in a satchel around his neck. He was shot down over Germany and captured. At the POW camp he was striped of everything but his satchel. When he later escaped he tried to make it across no-man’s-land were he was captured by the French. Thinking he was a German spy, he was sent to be executed. He managed to save himself by producing the coin which made the French verify his identity and saving his life.
Now challenge coins are carried by all members of the service to help build an esprit d’ corps. It, of course, has picked up little traditions along the way that seem to be agreed upon by everyone. One is that the coin must always kept free. This means that mounting it in a belt buckle or drilling a hole in it renders it useless as a challenge coin. Another is that it can not be kept in a wallet. There are two reasons for it. One is that it makes an indention in the wallet that looks like a condom and the other that it marks the wearer as a serviceman, not always a safe thing to do in some countries.
What evere the story behind their inception and use, challenge coins are now a military tradition.