Flying Tigers P-40 Warhawk by Gary Gay

Flying TigersNow the operational concept of air superiority could be achieved with an interception. Chennault continued expanding his intelligence base to achieve the destruction of the Japanese when two significant events occurred in 1942. First, a missionary, John Birch, escorted a downed pilot, Col James Doolittle, into Chennault’s headquarters. This prompted Chennault to formalize an underground railroad to repatriate shot-down pilots and offer further protection to his small force. Second, William J. Donovan visited the theater and asked for Chennault’s help in gathering intelligence. Chennault’s intelligence network grew slowly and quietly. More missionaries were recruited. Soon, Chennault’s agents were dispersed throughout occupied China, along the coast, and around Hankow, serving as liaisons between the Chinese armies and Chennault’s airmen, passing on information on subjects ranging from Japanese ship movements and troop activity to the black market. With this intelligence net, and intercepted radio traffic provided by captured Japanese signallers, Chennault’s force was secure and he increased his offensive effectiveness. A thorough appreciation for and analysis of time-distance relationships were the keys to interception. Battling the enemy over your lines or airfields meant that the enemy had probably already dropped his bombs.

[Illustration] - Japanese Mitsubishi A-6M Zero wreck at Guadalcanal Solomon Islands 1943

The idea was to intercept the attackers at a great distance from their target, either the airfield or front lines. Timely information from the early warning net and calculations from the net’s command post provided this information. Six variables had to be known and then the net could calculate the desired point of interception. The variables were:

(1) altitude and speed of enemy;
(2) rate of climb and speed of pursuit force;
(3) time for the pursuit to apply effective fire;
(4) time for collection of information from observers and transmission to the pursuit organization;
(5) time for the pursuit to leave the ground after receipt of orders;
(6) ability of pursuit to make interception by the shortest route.

Using simple algebra and updated reports from the early warning observers, the net command post could direct interception. The time-distance relationships were the underlying principle supporting Chennault’s doctrine of mobility, too. Presently, we refer to this as acting before the enemy can detect your actions or can react to your sudden move. Chennault employed mass and surprise to facilitate the destruction of the Japanese. Chennault did not wait for the command of the sky to take the war to the Japanese, rather he deflected the Japanese blows with his detection and interception while taking to the offense. He wrote: our only defense was a good offense. Chennault’s operational concept achieved two goals. First, he clarified and defined the China Theater‘s end state with the approval of Chiang Kai-shek and President Roosevelt. Second, he determined the means he could use from within the theater and he gathered the means from outside the theater that he needed to support Chiang’s Campaign. The essentials of Chennault’s security were the early warning net, deception, mobility, and a careful study of the enemy. His final task was to refine his plan and methods to defeat the Japanese.

Japanese planes destroyed on the ground during a U.S. bombing and strafing raid

Gen Claire Lee ChennaultAround the top-level conference table the war is a neat precise series of operations that come ready-made out of the planners’ briefcases, figured out to the last man, round of ammunition, and can of rations. These beautiful planning pictures quickly blur in the field. When the plans go awry, as they always do in varying degrees, it is the field commander who must take over and win or lose with what he has at the moment, not what the plans eventually call for. There is a tremendous gulf between military planners and military operators. Both are necessary, but it has been my experience that while an operator can be a planner, the planners seldom succeed in an operational command. Some of the biggest military busts of the war can easily be traced to putting a professional planner into an operational command. (Gen Claire L. Chennault)

Chennault, like many others in China, was unable to accomplish his objective. That is important, but not critical to this study. What is far more important is to note the tremendous contributions he made with the meager means available and to determine if his theory assisted in his campaign planning. From 1937 on, he believed that China‘s very limited internal lines of communication restricted Allied ground involvement as he relayed to Gen John Magruder, US Military Mission to China. Logistics and transportation limitations were the major reasons that Chennault sought to limit American involvement to small, mobile forces offset with superior intelligence and striking power. When he finally gained his small 500-plane force in the spring of 1944 instead of late 1941, its missions were diffused by the allied requirements. He could not mass on Japanese shipping and the mainland. He could only conduct offensive operations after providing protection for the War Department-controlled 20th Strategic Bomber Wing, protecting the Hump, supporting ground forces in Burma, and supporting the Chinese Army fighting against the Japanese Inchigo Offensive.

Hells Angel

Chennault’s overly optimistic 500 plane aerial offensive was inadequate to defeat Japan; however, without the divergent objectives pressed upon Chennault, the impact upon Japan would have been even greater. Since the history of the theater and its tactics were closely tied to the history of logistics, it is useful to examine how Chennault’s ways improvised to adapt to his meager means. The 14-AAF sent one bomber in at 200 feet to drop one bomb on a bridge instead of using the 8-AAF’s tactic of using a group with hundreds of bombs at thousands of feet to do a similar job. The 14-AAF used fighters as dive bombers to increase accuracy and borrowed Gen Kenney’s 5-AAF bomber tactic of using skip-bombing against ships.

Chennault calculated that it cost half a ton of supplies per month to support an American in theater so he worked with the National Resistance will of the Chinese to reduce his American overhead. The Americans operated at about half the normal troop strength and fought on one-fourth of the supplies usually allocated to an air force of its size. Chinese troops performed almost all the service functions for the 14-AAF. Chennault initiated this relationship with the arrival of the AVG and it continued until early 1945 when his growing forces overwhelmed the Chinese resources. The theater mastered improvisation from bomb racks to bamboo auxiliary fuel tanks. Gasoline was so critical that visiting planes flying into Chennault’s headquarters at Kunming, were drained of all but the absolutely essential fuel for the return trip. The early warning net and intelligence provided security for his theater.

Young provided one example in describing the early warning net around Chungking: the warning system was excellent. Probably the best in the world at the time. Spies with radios near enemy bases spotted the take-off and movements of enemy planes, telling the number and direction of flight [detection]. This, along with advice on the progress of the flights, was relayed to air defense headquarters in the threatened cities. Warnings there were given in the early stages by signals raised and lowered in high places, and then by sirens. People who could not take shelter had time to disperse in the countryside [protection]. The morale in Chungking was high, despite losses, at this stage of air bombardment.
Even without the means to offensively fight, Chennault had taken actions to preserve his fighting forces and his most important asset, the Chinese people
. (Adviser, Circa Jun 1937 – Jul 1941)


Most historians place the beginning of the second Sino-Japanese War during the Battle of Lugou Bridge (Marco Polo Bridge Incident) on July 7, 1937. Contemporary Chinese historians, however, place the starting point at the Mukden Incident of September 18, 1931. Following the Mukden Incident, the Japanese Guandong Army occupied Manchuria and established the puppet state of Manchukuo in February 1932. Japan pressured China into recognizing the independence of Manchukuo. Following the Battle of the Lugou Bridge in 1937, the Japanese occupied Shanghai, Nanjing, and Northern Shanxi as part of campaigns involving approximately 200.000 Japanese soldiers, and considerably more Chinese soldiers. Chinese historians estimate as many as 300.000 people perished in the Nanjing Massacre, after the fall of the city. The Marco Polo Bridge Incident not only marked the beginning of an open, undeclared, war between China and Japan but also hastened the formation of the second Kuomintang-Communist Party of China (CCP). The collaboration took place with salutary effects for the beleaguered CCP. The distrust between the two antagonists was scarcely veiled. The uneasy alliance began breaking down by late 1938, despite Japan‘s steady territorial gains in Northern China, the coastal regions, and the rich Yangtze River Valley in central China.

After 1940, the conflict between the Nationalists and Communists became more frequent in the areas outside Japanese control. The Communists expanded their influence wherever opportunities were presented, through mass organizations, administrative reforms, and land and tax reform measures favoring peasants – and the Nationalists attempted to neutralize the spread of Communist influence. The Japanese had neither the intention nor the capability of directly administering China. Their goal was to set up friendly puppet governments favorable to Japanese interests. However, the actions of the Japanese army made the governments that were set up very unpopular, and the Japanese refused to negotiate with either the Kuomintang or the Communist Party of China, which could have brought popularity. The Sino-Japanese War broke out days after Chennault’s arrival in Shanghai. While he went to China as a pursuit expert, his role was quickly broadened and within weeks he became Chiang’s Air Force Chief of Staff. Chennault did not wait for the formalities of the appointment to begin fighting. His defense of Shanghai and Nanking cited earlier, was vintage Chennault theory which included civil and base defense from the protection plank, and the detection and interception planks of his theory.

His hastily orchestrated defense with the best Chinese pilots that he, MacDonald, and Williamson could find, drove the Japanese to escorted bombing missions within a week and to night bombing within a fortnight. Chennault’s deceptive trap for the Japanese culminated in the biggest aerial battle in history up to that time, near Hankow on April 29, 1938. He coordinated for the Chinese and the Russian fighters and ground crews to noisily depart the area. Chennault was sure that Japanese spies would report this withdrawal. At sunset, the planes returned at a low level and landed without circling [protection through mobility]. The following morning the Japanese flew in for what they thought was a leisurely bombing of Hankow. After the battle, only three enemy planes returned to base while 36 were burning in the countryside [destruction].

Flying Tigers

American pilots of the Flying Tigers in Burma, by George Rodger (1941)

Over time, Chennault needed other resources as he could not overcome the superior Japanese numbers, higher quality pilots, and equipment. After a fair accounting of itself in late 1937 and early 1938, the Chinese Air Force had less than 20 obsolete aircraft and fewer capable pilots. Seven Russian fighters and five bomber squadrons provided most of China‘s air power until their withdrawal to the Russian western front. His first actions after the exodus and establishing his headquarters at Kunming were emplacing an early warning [detection] net over a landmass larger than half of the United States. He applied his educator’s mettle to reduce each task to its simplest element. He spent months with trainers and interpreters supervising training the Chinese to establish the multi-concentric net and command posts. The net saved tens of thousands of lives [protection] buying precious minutes for the civilian urban dwellers and laborers to seek air raid shelters before the Japanese bombers, often using incendiaries, struck. The net saved precious airplanes and dozens of airmen’s lives, also. Maps were general and very inaccurate. When pilots became lost, they were instructed to circle several times. Inevitably the radio silence would soon break giving them their location and the location of the nearest base. Chennault’s early warning net also provided him with an intelligence net that spanned occupied and unoccupied China [detection].

Map China 1940

The mainland was so massive that it was impossible for the Japanese Army to garrison the entire country. Early warning outposts that had been overlooked by the invaders remained in place and continued their observation. Other early warning posts infiltrated the Japanese lines and operated with great success. The early warning net was the heart of the downed pilot’s recovery effort. Chennault initiated the blood chit; pilots wore painted cloth stitched on their jackets, with directions for repatriation and reward written in Burmese and Chinese. Chennault’s protection doctrine minimized casualties and aircraft losses and maximized downed pilot recoveries. Likewise, Chennault trained the CAF and coordinated combat actions with the Russian squadrons for the protection of their bases, support to the army, and protection of
Chungking. The former headmaster established classes that he would repeat later for the AVG. Later as his missions and resources expanded he had to delegate trusted subordinates to train the new pilots of the Chinese Air Task Force and the 14-AAF. After training 11 classes of CAF pilots, Chennault remained frustrated and felt that there was more he could do to contribute to the war against Japanese aggression. In October 1940, Chiang sent him to Washington to plead China‘s case to receive weapons for war, including 500 planes and Americans to fly them.


(Etymology) 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, representing a debt to be paid; it is an Anglo-Indian word dating from the late 18th century, derived from the Hindi Citthi. The first blood chit may have been made in 1793 when French balloonist Jean-Pierre Blanchard (see Short History of the Parachute – Doc Snafu) demonstrated his hot air balloon in the United States. 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. During 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 British officer John Masters recorded in his autobiography that Pathan women in the North-West Frontier Province (1901–1955) of British India (today 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 the American Volunteers Group and the 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 United States officially entered WW-II in December 1941, flight crew survival kits included blood chits printed in 50 different languages that sported an American 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.

US Blood Chit (CBI)(alexander auctions)

Japanese troops advance on a Burmese oil field, 1942

The sudden Japanese offensive in Burma threatened Chiang’s and Chennault’s LOC (Localizer) if the offensive was not stopped before reaching Dinjau, India, the northwestern terminus of the Hump (Air Route over the Himalayas). The Japanese were advancing on two fronts. The Allied air forces coordinated attacks with ground forces withdrawing toward India. The Japanese were halted at the Irrawaddy River. Chennault felt that bombers were so indispensable to the China Theater that he created bombers from the AVG’s P-40 pursuit planes. His mechanics fashioned homemade bomb racks and pilots dropped combinations of homemade, Chinese, and Russian bombs.

Map showing military airlift route over the Himalayas between Assam, India and Kunming, China, known as The Hump. Also shown is the planned route of the Ledo Road to connect to the Burma Road. The shaded area is Japanese-occupied Burma

Previous articleAIR Operations – China Burma India (Maj Edward M. Hudak)
Next article24th Infantry Division (Mindanao – Philippine Islands) Apr-Aug 1945