Operation Ichi-Go
Operation Ichi-Go was a campaign with several battles between the Imperial Japanese Army forces and the National Revolutionary Army of the Republic of China, fought from April to December 1944. It consisted of three battles in the Chinese provinces of Henan, Hunan and Guangxi.
These battles were the Japanese Operation Kogo or Battle of Central Henan, Operation Togo 1 or the Battle of Changheng, and Operation Togo 2 and Togo 3, or the Battle of Guilin–Liuzhou, respectively. The two primary goals of Ichi-Go were to open a land route to French Indochina, and capture air bases in southeast China from which American bombers were attacking the Japanese homeland and shipping.
In Japanese the operation was also called Tairiku Datsū Sakusen, or "Continent Cross-Through Operation", while the Chinese refer to it as the Battle of Henan-Hunan-Guangxi.
Background
Japanese planning
By early 1944, Allied victories in the Pacific were eroding the Japanese defensive perimeter. Japan decided to attack in Burma and China to improve its position; these became Operation U-Go and Ichi-Go respectively. Ichi-Go corresponded with an Imperial General Staff contingency plan to the loss of the Western Pacific; the plan was for securing an overland rail route through French Indochina and China for raw materials from south-east Asia, which would be used to develop offensives in 1946. The objective for Ichi-Go approved by Emperor Hirohito on 24 January 1944 was the neutralization of USAF bases in China, particularly the XX Bomber Command bases near Chengdu, Sichuan. China Expeditionary Army, commanded by General Shunroku Hata, expanded the objectives in its operational planning to include securing overland routes and neutralizing China by destroying Chinese forces. Ichi-Go may also have been intended to force the Allies to open peace negotiations, and give Japan a better negotiating position. General Yasuji Okamura was placed in charge of Ichi-Go.By early February, preparations along the Yangtze included repairs to a major bridge and air field maintenance.
The IJA mobilized 500,000 troops, 100,000 horses, 1,500 pieces of artillery, 800 tanks, 15,000 mechanised vehicles, and 200 bombers for the offensive. They were supplied with eight months of fuel and two years of ammunition. According to historian Hara Takeshi, it was "the largest military operation carried out in the history of the Japanese army".
Chinese planning
The Chinese economy started collapsing in 1941. China entered the war in 1937 with a primarily agrarian economy and quickly lost much of its industrial capacity to the Japanese. Maintaining the forces needed to stay in the war imposed an unsustainable burden on an economy further weakened by blockade, shortages of staple goods, poor weather, and inflation; there was widespread famine from 1942. The government responded to the economic pressure, reduced Japanese activity after December 1941, and the lack of offensive capability by encouraging the military to produce its own food. Some troops went further by entering industry and smuggling. The self-sufficiency drive and the lack of military action reduced military preparedness and increased corruption. By Ichi-Go, the effectiveness of the Chinese military had "plummeted".Allied strategy affected Chinese preparations. At the Cairo Conference in November 1943, China agreed to major combined operations in Burma on the condition that the Western Allies committed significant resources. No such commitment occurred. A few days later at the Tehran Conference, the Western Allies and the Soviet Union agreed to prioritize the European theater. In January 1944, Chiang warned US President Franklin D. Roosevelt that prioritizing Europe would encourage Japan to attack and knock China out of the war. In late-March, China believed a Japanese offensive was "imminent"; the US received corroborating reports from Clarence E. Gauss, the American ambassador to China. China sought to reinforce the defense with Yunnan-based Y Force, which was earmarked for Burma; Y Force was an American trained and equipped National Revolutionary Army unit and some of the best troops available to China. In early April, the US threatened to halt Lend-Lease to China if Y Force was withheld from Stilwell in Burma. Ultimately, Y Force joined the Allied campaign in Burma in mid-May as Ichi-Go was underway.
Chinese intelligence also misassessed indicators. It estimated that the Yangtze bridge would not be usable until May, and that Japanese troop movements in the north were a feint. On 27 April, after the start of Ichi-Go, China received French intelligence from Indochina of the Japanese goal of securing the rail corridor. The intelligence was disregarded as Japanese misinformation to draw forces away from Burma. The Chinese could not independently verify significant Japanese movements in central and southern China. Only 30,000 Japanese troops were detected operating in the north, which suggested a localized effort. The Chinese expected a larger attack in southern China, a belief that persisted into May.
Campaign
Henan
The first phase of Ichi-Go, codenamed Kogo, was for capturing the Beijing–Hankou railway in Henan and destroying the ROC's First War Zone. Kogo involved 60,000–70,000 Japanese troops. The First War Zone was commanded by General Jiang Dingwen with General Tang Enbo as deputy. It had only 6,000-7,000 troops, or 60% to 70% of its authorized strength. USAF General Claire Chennault described the troops as a "poorly disciplined mob". Overall, there were 400,000 Chinese troops in northern China.Kogo opened on 17 April, broke through the defenses by the end of the 18 April, and took Xuchang a week later. Divisional commander Lu Gongliang, deputy divisional commander Huang Yonghuai, and two regimental commanders were all killed the day Xuchang fell on 1 May and none of the officers of the divisional headquarters was found after the defenders broke out from the city. Tang's 31st Army Group reported the casualties of the New 29th Division - fighting in central Henan and Xuchang - as 4,092 killed, wounded, or missing. Senshi Sōsho, the official Japanese military history, put Chinese losses at 2,432 killed and 858 captured and Japanese losses at 50 killed and 149 wounded.
Chinese communications were poor and the defense of Luoyang was uncoordinated. Chiang intended to allow the Japanese to close around Luoyang - the city was fortified and contained provisions for weeks - and then attack the flanks once the Japanese became overextended; this tactic had been used successfully before to defend Changsha. According to Jiang, he requested permission to attack as early as 23 and 24 April, but did not receive Chiang's permission until 1 May; by that time the Japanese had advanced too far. Poor communications also hampered the direction of reinforcements to Luoyang. The Japanese encircled Luoyang on 14 May and captured the city on 25 May. The Chinese lost more than 19,000 troops from the three divisions defending the city. On 26 May, the Japanese Army reported Chinese casualties as 4,386 killed and 6,230 captured, and Japanese casualties as 80 killed and 281 wounded.
At the same time as the battle of Luoyang, Chinese 36th Army Group retreated and its commander, Lieutenant general Li Jiayu, was killed. The Japanese pursued Tang's westward retreat as far as the Tong Pass. Combined with an advance north from Wuhan, the Japanese captured the railway.
Contemporary Chinese analysis identified additional factors for the collapse of the First War Zone, some of which were related to the general degeneration of the Chinese military. According to one critic, Tang's command and control was poor and he abandoned his army; Tang was generally seen to have been in effective control of the First War Zone. The local population - alienated by wartime deprivation, state corruption, and the First War Zone's aggressive requisitions - also withheld support. Incidents included civilians attacking Chinese troops, stealing abandoned weapons, and refusing to obey orders to destroy highways. According to American reports, Kogo met only "token resistance". Theodore H. White observed Chinese officers neglecting their duties and that within three weeks "a Chinese army of 300,000 men had ceased to exist".
The First War Zone suffered heavy casualties in the battle for central Henan. Tang Enbo's 31st Army Group alone reported its losses as 58,036 killed, wounded, or missing. Combined with the losses of other regular Chinese units in major battles in Henan, the total casualties of the First War Zone are as high as 100,000. Senshi Sōsho put Chinese losses from the start of the operation until the capture of Luoyang at approximately 37,500 killed and approximately 15,000 captured and Japanese losses in the same period at approximately 850 killed and approximately 2,500 wounded.
Hunan
The next phase was Togo 1 with the objective of securing the Guangzhou–Hankou railway from Wuhan to Hengyang. Togo 1 started on 27 May and involved 200,000 Japanese troops advancing south from Wuhan to Changsha. Central China was defended by another 400,000 troops. The ROC's Ninth War Zone, commanded by General Xue Yue, defended Changsha; it had held the city against three Japanese campaigns from 1939 to 1942; as in those engagements, Ninth War Zone strategy was a fighting withdrawal to the city combined with scorched earth. Togo 1 was much larger than the previous campaigns, advancing in three - rather than one - columns over a 150 kilometer-wide front; it was also adequately supplied. On 29 May, the ROC Military Affairs Commission ordered Changsha to be held to defend USAF air bases and maintain American confidence; the option of abandoning railway and retreating south-east to Guilin was rejected. Chiang refused to send supplies to Changsha because he believed Xue was disloyal.The Japanese reached Changsha in early June. The city was defended by three understrength Chinese divisions commanded by General Zhang Deneng; two of the divisions and the artillery were on Yuelu Mountain south of the city across the Xiang River. Unlike the previous campaigns, it was the Chinese who were outnumbered with 10,000 troops against 30,000 Japanese. One of the two attacking Japanese divisions had urban warfare training. Japanese bombers attacked the artillery on Yuelu, while infantry moved around the city to attack from the south. Zhang's redeployment of troops from the city to reinforce Yuelu disorganized the defense; Chinese staff officers were unable to organize movement over the Xiang, leaving many units "stranded", and unclear orders made many troops believe that they were to retreat. The Japanese took Changsha on 18 June after three days of fighting. The Chinese withdrew from Yuelu the same day leaving two companies in the city.
Xue retreated south to Hengyang. The city was defended by 18,000 troops. USAF Fourteenth Air Force, commanded by Chennault, provided limited support; it was also tasked with protecting USAF XX Bomber Command's bases and supporting the Allied Burma offensive. The defenses included concrete fortifications, and was well provisioned with artillery, anti-tank guns, and supplies. Two large reserve groups were placed to threaten the Japanese flanks. Chiang assigned General Fang Xianjue, whom he trusted, to command the city, A relief force from Guangdong was organized. On 25 June, the Japanese captured a major nearby US air base. Afterwards, the Japanese 68th and 116th Division attacked Hengyang from the west and south. The flooded paddy fields and canals to the west made the use of tanks difficult. To the south were hills. The attack was halted with heavy casualties on both sides. The Japanese paused to reinforce their air forces and resupply. On 11 July, after five days of heavy fighting, the Chinese fell back to another line. The Japanese paused again to bring up reinforcements of one division and several brigades. The Japanese sought to destroy Chinese reserves to reduce the defenders' morale. Air attack destroyed much of the city. By the end of July, there was a food shortage in Hengyang. Chiang did not resupply the city. Stilwell - who controlled Lend-Lease in the Chinese theater - refused Chennault's request to divert 1,000 tons of supplies to Hengyang; according to the United States Army's official history, Stilwell believed that Chinese politics would prevent the supplies from being used against the Japanese. Five Japanese divisions resumed the attack on 3 August, broke through the northern wall 7 August, and captured the city by the morning of 8 August.