Blood chit is a notice that is carried by the military, usually aircraft personnel, that displays messages aimed at the civilians that ask them to help the service member in case they are shot down. Alternative names are escape and identification flags (Chinese: 人物證明書; pinyin: rénwù zhèngmíng shū). Chit (also ‘chitty’) is a British English term for a small document, note or pass; it is an Anglo-Indian word dating from the late 18th century, derived from the Hindi citthi.
The idea of blood chit originates from 1793 when French balloonist Jean-Pierre Blanchard demonstrated his hot air balloon in the USA. Because he could not control the direction of the balloon, no one knew where he would land. Because Blanchard did not speak English, George Washington gave him a letter that said that all US citizens were obliged to assist him to return to Philadelphia.
In World War I, British Royal Flying Corps pilots in India and Mesopotamia carried a “goolie chit” printed in four local languages that promised a reward to anyone who would bring an unharmed British aviator back to British lines. The term “goolie” is British slang for “testicles” and was so called (and still is called by the Royal Air Force) because, in the areas where the chits were used, local tribesmen were said to turn over aviators to their womenfolk, who castrated the pilots for use as servants. But the British officer John Masters recorded in his autobiography that Pathan women in the North-West Frontier Province (1901–1955) of British India (now modern day Pakistan) during the Anglo-Afghan Wars would behead and castrate non Muslim soldiers who were captured, like British and Sikhs.
In the Second Sino-Japanese War prior to World War II, foreign volunteer pilots of Flying Tigers carried notices printed in Chinese that informed the locals that this foreign pilot was fighting for China and they were obliged to help them. A text from one such blood chit translates as follows:
“I am an American airman. My plane is destroyed. I cannot speak your language. I am an enemy of the Japanese. Please give me food and take me to the nearest Allied military post.
You will be rewarded.”
When the USA officially joined the war in 1941, flight crew survival kits included blood chits printed in 50 different languages that sported a US flag and promised a reward for a safe return of a pilot. The kit might also include gifts like gold coins, maps or sewing needles. Many US flight crews that flew over Asia had their “blood chit” sewn to the back of their flight jackets. Some units added the blood chit to the crew's flight suits while other units gave the blood chit out only for specific flights.