This was the US unofficial designation of the operation by the survivors of Colonel Charles N. Hunter’s (previously Brigadier General Frank D. Merrill’s) 5307th Composite Unit (Provisional), otherwise known as ‘Merrill’s Marauders’, and the Chinese New 30th and 38th Divisions against Myitkyina in northern Burma (May/August 1944).
Myitkyina was held by elements of Lieutenant General Shinichi Tanaka’s 18th Division, of Lieutenant General Masaki Honda’s 33rd Army, and this garrison was believed by Lieutenant General Joseph W. Stilwell, heading the Chinese-US Northern Combat Area Command, to pose a threat to the new supply road being built to China from Ledo.
An extremely difficult and gruelling approach march was launched by the Chinese Army in India (General Cheng Tung-kuo’s New 1st Army comprising Lieutenant General Liao Yao-hsiang’s New 22nd Division, Lieutenant General Hu Su’s New 30th Division and Lieutenant General Sun Li-jen’s New 38th Division) in October 1943, and was seriously checked by Tanaka’s 18th Division in the Hukawng valley.
Then the advance of Stilwell’s forces, whose Chinese element was commanded tactically by Sun, was speeded by the arrival of Merrill’s 5307th Composite Unit (Provisional) at Sharawga on 21 February 1944, allowing a change in tactics to Chinese pinning attacks and US outflanking attacks. Aided by a diversion in Japanese strength to deal with the ‘Thursday’ 2nd Chindit Expedition, the US and Chinese forces closed on Myitkyina, the northernmost river port and railway terminus in Burma, from the north (5307th Composite Unit and the New 30th Division from Ritpong) during May.
On 17 May a 60-mile (95-km) approach march over the 6,550-ft (2970-m) Kumon mountains, with mules to carry supplies, came to an end outside Myitkyina. Here about 1,300 survivors of the 5307th Composite Unit (Provisional), together with units of the Chinese 42nd and 150th Regiments of the ‘X’ Force, attacked the unsuspecting Japanese holding Myitkyina airfield. The attack was completely successful in itself, but Stilwell knew that an immediate follow-on attack to take Myitkyina itself was virtually impossible for lack of strength. Even so, an initial assault was undertaken by elements of the two Chinese regiments, but was defeated with heavy losses. The primary reason for this was the fact that the NCAC intelligence staff had seriously underestimated the Japanese strength in the town, which had been reinforced and now totalled some 4,600 well-armed men.
Weakened by hunger and disease, and affected by steadily deteriorating morale, the 5307th Composite Unit (Provisional) and the Chinese continued fighting through the height of the monsoon season. The area around Myitkyina had the largest reported incidence of scrub typhus, which spread through the ‘Marauders’. Even so, the US troops attacked and then defended in a see-saw series of vicious infantry engagements.
Another attempt was made by the tired forces in late July, after the Chinese New 22nd and 38th Divisions had advanced from the west, facilitated by the fact that the Chindits’ radically reduced and totally exhausted Indian 77th Brigade, under the command of Brigadier J. M. Calvert, had taken Mogaung on on the line of the railway and river to the south, during 26 June.
Finally, after a Chinese division had arrived by air on the airfield, the US and Chinese troops managed to enter and take Myitkyina on 4 August after Tanaka, realising that Myitkyina was no longer tenable, and about 600 of his men escaped on 3 August. Some 187 Japanese soldiers were taken prisoner, and this meant that about 3,800 Japanese soldiers had been killed in combat. The ‘Marauders’ had lost 272 men killed, 955 wounded, and 980 evacuated for illness and disease. Other men died later from cerebral malaria, amoebic dysentery, and/or scrub typhus.