On 7 July 1937, the Imperial Japanese Army launched a full-scale invasion of China. With the onset of the war, Beijing and Tianjin fell to the Japanese in less than one month, which exposed the entire North China Plain to the Japanese Army. On 12 November, the Japanese Army captured Shanghai. Nanjing was at risk of being besieged, and the Chinese government was forced to transfer its capital to Chongqing.
However, the Chinese government did not transfer its elite troops and the war facilities to Chongqing immediately; instead, they were gathered together and set up in Wuhan. Assistance from the USSR provided additional military and technical resources, including a small band of Soviet Air Force volunteers.
Wuhan, located halfway up the Yangtze River, was the second largest city at the time with a population of two million. The city was divided by the Yangtze River and Hanshui into three regions: Wuchang, Hankou and Hanyang. Wuchang was the political center, Hankou was a commercial district while Hanyang was the industrial estate. After the completion of the Yuehan Railway, the importance of Wuhan as a major transportation hub in inland China was further established.
When Japan captured Nanjing on 13 December, the Chinese shifted structures and industries to Wuhan. Although Chongqing was officially chosen as the new political headquarter, Wuhan virtually became the political, economic and military center at the time; and the wartime capital of China at the onset of the engagements in Wuhan. The Chinese war effort was focused on protecting Wuhan from being occupied by the Japanese. The Japanese government and the headquarters of the China Expeditionary Force thereby expected that the fall of Wuhan would lead to the end of Chinese resistance.
As a result of the Second United Front, the first People's Political Council was opened in Hankou on 6 July 1938, and the New Fourth Army was established on 25 December 1937 in Hankou with a strength of around 10 thousand.
The Battle of Wuhan was preceded by a Japanese air strike on 28 February 1938. It was known as the 2.28 Air battle and the Chinese were able to repel the attack.
On 24 March, the Diet of Japan passed the National Mobilization Law that authorized unlimited funding of war. As part of the law, the National Service Draft Ordinance also allowed the conscription of civilians.
On 29 April, the Japanese air force launched major air strikes on Wuhan to celebrate Emperor Hirohito's birthday. The Chinese, knowing this beforehand, were well prepared. This battle was known as the 4.29 Air battle, one of the most intense air battles of the Second Sino-Japanese War. The ROCAF shot down 21 Japanese planes at a loss of 12.
After the fall of Xuzhou in May 1938, the Japanese planned an extensive invasion of Hankou and the takeover of Wuhan, intending to destroy the main force of the National Revolutionary Army. The Chinese, on the other hand, were preparing for the defense of Wuhan. They managed to gather up more than one million troops, around 300 planes and 50 naval ships.
In an attempt to buy more time for the preparation of the defense of Wuhan, the Chinese opened up the dikes of the Yellow River in Huayuankou, Zhengzhou on 9 June. The flood, known now as the 1938 Yellow River flood, forced the Japanese to delay their attack on Wuhan. However, it also caused somewhere around 500,000 civilian deaths.
On 13 June, the Japanese made a naval landing and captured Anqing, which signaled the onset of the Battle of Wuhan. On the southern bank of the Yangtze River, the Chinese 9th Military Region stationed one regiment west of Poyang Lake, and another regiment between the line from Jiangxi to Jiujiang. The main force of the Japanese 11th Army attacked along the southern shore of the river. The Japanese Namita detachment landed in the east of Jiujiang on 23 July.
The Chinese defenders tried to resist the attack, but they could not repel the landing force of the Japanese 106th Division from capturing Jiujiang on the 26th. The Namita detachment moved eastward along the river, and landed northeast of Ruichang on 10 August and began laying siege to the city. The defending 3rd Chinese Army (Group?) were reinforced by the 32nd Army Group and resisted. However, when the Japanese 9th Division entered the action, the Chinese defenders were exhausted and Ruichang was eventually captured on the 24th.
The 9th Division and the Namita detachment continued to move eastward along the river, while the 27th Division invaded Ruoxi simultaneously. The Chinese 30th and 18th Armies resisted along the Ruichang-Wuning Road and the surrounding area, and the situation was in stalemate for months. On 5 October, after the Japanese 27th Division captured Ruoxi, they turned to strike northeast, capturing Xintanpu in Hubei on the 18th and then moving toward Dazhi.
In the meantime, the Japanese Army and their supporting river fleet which had advanced eastward along the river encountered resistance from the defending Chinese 31st Army Company and 32nd Army Group in the west of Ruichang. When Matou Town and Fuchikou (in Yangxin County) were captured, the Chinese 2nd Army Group organized the 6th, 56th, 75th and 98th along with the 30th Army Group to strengthen the defense of the Yangxin region. The battle continued until 22 October when the Chinese lost all of Yangxin, Dazhi and Hubei City. The Japanese 9th Division and Namita detachment was now approaching Wuchang.
While the Japanese Army was attacking Ruichang, the 106th Division separately moved southward along the Nanxun Railway (Nanchang-Jiujiang). The defending Chinese 1st and 29th Army Group and the 4th, 8th Army relied on the advantageous terrain of Lu Shan and north of Nanxun Railway to provide resistance. As a result, the Japanese offensive suffered a setback. On 20 August, the Japanese 101st Division crossed the Poyang Lake from Hukou County to reinforce the 106th Division.
They breached the Chinese 25th Army's defensive line and captured Xinzhi, coordinating with the 106th Division in an attempt to occupy De'an and Nanchang, to protect the south side of the Japanese Army advancing westward. Xue Yue, the commander-in-chief of the Chinese 1st Army Group, used the 66th, 74th, 4th and 29th Army to coordinate with the 25th Army to fight the Japanese in Mahui Summit and north of De'an. The battle was in a stalemate.
Near the end of September, the Japanese 123rd, 145th, 147th, 101st and 149th Regiment of the 106th Division advanced into the Wanjialing region, west of De'an. Chinese general Xue Yue commanded the 4th, 66th and the 77th Army to outflank the Japanese. The 27th Division of the Japanese Army attempted to reinforce the position, but were repulsed by the Chinese 32nd Army in Baisui Street, west of Wanjialing.
On 7 October, the Chinese Army launched their final attack on the encircled Japanese troops. The fierce battle continued for three days, and all Japanese counter-attacks were repelled by the Chinese. Because of their isolation, and the lack of supplies, the four Japanese regiments were annihilated by the 10th. It was known to the Chinese as the Victory of Wanjialing.
North of the Yangtze River, the Japanese 6th Division of the 11th Army Group struck Taihu from Anhui on 24 July. They breached the defensive lines of Chinese 31st and 68th Army and captured Taihu, Susong, Huangmei (belonging to Hubei) regions on 3 August. As the Japanese continued to move westward, the Chinese 4th Army Group of the 5th Military Region set their main force in Guangji, Hubei and Tianjia Town to intercept the Japanese. The 11th Army Company and the 68th Army were ordered to defend tenaciously on the defensive line in Huangmei region, while the 21st, 26th and the 29th Army Company were shifted south to flank the Japanese.
The Chinese recaptured Taihu, Susong on 28 August. With the momentum, the 11th Army Company and the 68th Army launched counter-offensives, but were unsuccessful. They retreated to the Guangji region to coordinate with the Chinese 26th, 86th and 55th Army to continue to resist the Japanese Army. The 4th Army Group ordered the 21st, 29th Army Company to flank the Japanese from northeast of Huangmei, but they were unable to stop the Japanese. Guangji and Wuxue were captured sequentially.
The Japanese Army then lay siege to Tianjia Town Fort. The 4th Army Group used the defending 2nd Army to strengthen the 87th Army's base, and the 26th, 48th and 86th Army to coordinate and flank the Japanese. However, they were suppressed by the superior Japanese firepower and experienced high casualties. The Tianjia Town Fort was captured on the 29th, and the Japanese continued to attack. They captured Huangpo on 24 October and were now approaching Hankou.
In the north of Dabie Mountains, the 3rd Army Group of the 5th Military Region stationed the 51st Army, 19th Army Group and the 77th Army in the Liuan, Huoshan regions in Anhui. The 71st Army was stationed in Fujin Mountain, Gushi County (Henan) regions. The 2nd Army Company was stationed in Shangcheng County, Henan and Macheng, Hubei. The 27th Army Group and the 59th Army was stationed in Yellow River region, and the 17th Army was in Xinyang region to organize the defensive works.
The Japanese attacked in late August with the 2nd Group Army marching from Heifei on two different routes. The south route of 13th Division breached the Chinese 77th Army's defensive line and captured Huoshan, turning towards Yejiaji. The nearby 71st Army and the 2nd Army Company used the existing base and forcefully resisted. The Japanese 13th Division was baffled and required the 16th Division to reinforce. On 16 September, the Japanese captured Shang City. The defenders retreated to south of Shang City, relying on the strategic pass of Dabie Mountains and continued to resist. On 24 October, the Japanese were approaching Ma City.
The Japanese Army in north route was the 10th Division. They breached the Chinese 51st Army's defensive line and captured Liuan on 28 August. On 6 September, they captured Gushi and proceeded to move westward. The Chinese 27th Army Group and the 59th Army gathered up in the area of Yellow River to organize resistance. After ten days of struggle, the Japanese captured Yellow River on the 19th. On the 21st, the Japanese 10th Division pierced through the base of Chinese 17th Army Group and 45th Army, and captured Luoshan.
Then they continue to move westward, but experienced Chinese counter in the east of Xinyang and was forced to withdraw back to Luoshan. The Japanese 2nd Army Group used the 3rd Division to reinforce, and work in coordination with the 10th Division to attack Xinyang. On 6 October, a unit of Japanese Army detoured south of Xintang and captured Liulin station of Pinhan Railway. On the 12th, the Japanese 2nd Army Group captured Xinyang, and moved southward along the Pinhan Railway to coordinate with the 11th Army Group on invading Wuhan.
By now, the Japanese Army had completed the encirclement of Wuhan. The Chinese Army, hoping to save their existing strength, abandoned the city. The Japanese Army captured Wuchang and Hankou on the 26th, and captured Hanyang on the 27th.
According to Yoshiaki Yoshimi and Seiya Matsuno, Emperor Shōwa authorized, by specific orders (rinsanmei), the use of chemical weapons against the Chinese. During the battle of Wuhan, Prince Kan'in transmitted the emperor's orders to use toxic gas 375 times, from August to October, 1938, despite the 1899 Hague Declaration IV, 2 - Declaration on the Use of Projectiles the Object of Which is the Diffusion of Asphyxiating or Deleterious Gases, Article 23 (a) of the 1907 Hague Convention IV - The Laws and Customs of War on Land, and Article 171 of the Versailles Peace Treaty. According to another memo discovered by historian Yoshiaki Yoshimi, Prince Naruhiko Higashikuni authorized the use of poison gas against the Chinese on 16 August 1938. A resolution adopted by the League of Nations on 14 May condemned the use of toxic gas by the Imperial Japanese Army.
Despite the eventual capture of Wuhan, the Japanese suffered heavy casualties, preventing them from starting other successful large scale offensives. During this battle, the Japanese army suffered over 140,000 casualties. Although Chinese casualties were more than double this number at 400,000, it was an improvement from the Battle of Shanghai, where the Chinese to Japanese casualty ratio was nearly 3.6 : 1.
After the capture of Wuhan, the advance of Japanese Army in central China were slowed down further by several battles around Changsha in 1939, 1941, and 1942. No other major offensives were launched until Operation Ichi-Go in 1944. The Chinese Army managed to preserve strength for the continuation of battle against the weakened Japanese Army. The Japanese's pre-war hopes for a final showdown in Wuhan, to annihilate the main forces of the Chinese Army and forcing them to surrender were unsuccessful. At the conclusion of the battle, Japan had only one division remaining in the home island and was unable to reinforce the 7 divisions of Kwantung Army in Northeast China and Korea facing 20 Soviet Far East divisions stationed on the border.