The
Japanese invasion of Burma began in January 1942, and Japan conducted
a series of air raids over
Rangoon, where the headquarters of the
Burma Corps of the
British Indian Army was located. To relieve Allied positions in Burma, the Chinese Expeditionary Force (CEF) was formed from the
Fifth Army and the
New Sixth Army, under the command of American Lieutenant General
Joseph Stilwell. The CEF entered Burma in February 1942 and engaged with the Imperial Japanese Army at the
Toungoo. Stilwell arrived at the front on March 22, and the Chinese
200th Division held for twelve days against overpowering Japanese forces before retreating. The setbacks against the Japanese Army escalated the tension between Stilwell and Chiang, as many Chinese commanders refused to carry out orders from Stilwell without approval from Chiang first. The Japanese soon
captured Rangoon in March and advanced toward the Burma Road. The
1st Burma Division of the British Indian Army were encircled by the Japanese at the oil fields in the
Battle of Yenangyaung on April 18, and the 38th Division led by Lieutenant General
Sun Li-jen attempted to relieve them. The Allied forces led by the British decided to evacuate from Burma after
Lashio fell to the Japanese on April 29. In response, Stilwell ordered a general retreat to India. The majority of the Fifth Army, led by
Du Yuming, however attempted to retreat to
Yunnan through
primitive forests in Northern Burma. The units were decimated by Japanese ambush along with malaria and dysentery, suffering major losses. The failure of the first expedition led to the closure of the Burma Road, and future Chinese war efforts had to rely on
the Hump and the construction of the
Ledo Road for logistical support. == Second expedition (Early 1943 – March 1945) ==