Operation Ichi-Go (Japanese: 一号作戦, romanized: Ichi-gō Sakusen, lit. 'Operation Number One') 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 (大陸打通作戦), or "Continent Cross-Through Operation", while the Chinese refer to it as the Battle of Henan-Hunan-Guangxi (simplified Chinese: 豫湘桂会战; traditional Chinese: 豫湘桂會戰; pinyin: Yù Xīang Guì Huìzhàn).
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 (CEA), 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 — albeit 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 (NRA) 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 (呂公良), deputy divisional commander Huang Yonghuai (黃永淮), 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 Enbo 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 killed, wounded, or missing 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. Deputy commander-in-chief Tang Enbo reported the losses of the 28th and 31st Army Groups alone 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.
On June 11, Lieutenant General Hikosaburō Hata, deputy chief of staff of the Imperial General Headquarters, arrived in Zhengzhou from Central China and received a report from Lieutenant General Eitaro Uchiyama, commander of the Twelfth Army, regarding the general progress of the Beijing–Hankou operation. On June 15, Lieutenant General Hata returned to Tokyo and reported to the Imperial General Headquarters that :
- Of the forty-three Chinese divisions deployed in the Beijing–Hankou operation, 60% suffered devastating losses and only 15% remaining unscathed. The First War Zone suffered severe material and morale damage and was estimated to be unable to recover before the end of the year.
- During the Beijing–Hankou operation, the Chinese Air Force flew approximately 400 sorties while the Japanese Air Force flew 2,700 sorties, approximately seven times that of the Chinese's.
- The number of Japanese soldiers killed in action accounted for one percent of the participating forces, the number of wounded accounted for three percent, and the number of those who fell ill accounted for five percent.
- Of the 255 tanks from the 3rd Tank Division that participated in the operation, one-third were no longer operational. Only nine tanks were destroyed—seven from landmines and two from artillery. Repairs would likely take a considerable amount of time.
- A regiment of the 37th Division advanced 500 kilometers in 20 days, averaging 27 kilometers per day.
Shaanxi
To support the Twelfth Army's operation in Henan, the Japanese First Army in Shanxi crossed the Yellow River near Yuanqu on May 9 and captured Shan County and Daying in Shaanxi on May 18. Given the concentration of retreating troops of the Chinese First War Zone and reinforcements from Hu Zongnan's Eighth War Zone, the First Army considered the possibility of a Chinese counterattack on Shan County and other areas, deeming it necessary to strike first to seize the initiative. Upon learning of the First Army's operational plan and discussing with the commander of the First Army, General Yasuji Okamura, commander of the North China Area Army, approved of the offensive operation and transferred units of the Twelfth Army such as the 3rd Tank Division with a one-week deadline for their return. On June 1, the Chinese Army under Hu Zongnan launched its offensive towards Shan County. Despite inflicting heavy casualties on certain units of the Japanese 69th Division, the attack ultimately stalled after three days. On June 5, the Japanese Army launched its offensive towards Lingbao but it did not proceed as expected with slow progress and heavy losses due to unexpected strong Chinese resistance. The First Army lost contact with its units and for some time was unaware of the battlefield situation. As the deadline on June 10 approached, the First Army was anxious and mobilized the reserve force in Nancun. At the same time, the Chinese defenses were showing signs of breaking and some units began retreating without orders. By midnight, the Chinese Army was ordered to retreat and the Japanese Army gave chase on June 11 with its tank division. Having achieved its operational objective of defeating the eastward-advancing troops of the Eighth War Zone, the Japanese Army ordered a withdrawal on June 12, swiftly restoring their original positions.