On September 15, 1941, the Japanese 11th Army set up a headquarters combat command post in Yueyang, and convened a meeting of the chiefs of staff of each unit to check the preparations for launching the Battle of Changsha. The army finalized the battle plan in early September:

First, the purpose of the operation: to attack Changsha, destroy the Chinese army's anti-Japanese war attempt, deal a heavy blow to the army of the Ninth Western Theater, and completely crush the fighting spirit of the Chinese soldiers.

Second, the start time of the campaign: It was decided to start the offensive on September 18.

3. Combat units: The total strength of the ground forces of the 11th Army for offensive operations in Changsha is 45 infantry brigades, 26 artillery brigades, and a number of naval and aviation units.

In order to contain the troops of China's Ninth Theater of Operations, the Japanese command post ordered the corps stationed along the Nanxun line (Nanchang side) to launch an attack at an appropriate time.

After the First Battle of Changsha in the autumn of 1939, the Ninth Theater continued to form a wide frontal confrontation with the Japanese 11th Army in the area south of the Yangtze River across Hunan, Hubei and Jiangxi provinces. After the Sixth War Zone was re-established in July 1940, the boundary between the Ninth War Zone and the Sixth and Fifth War Zones to the west and north was Shimen Bridge south of Changde, the south bank of Lianshan Lake, the north shore of Datong Lake, and the north bank of Dongting Lake along the Yangtze River to the lower reaches of Wuhan to the Jiujiang River; To the east, the boundary with the Third War Zone is the line of the Fuhe River and the mouth of Poyang Lake. Together, these theaters constituted an encirclement posture against the 11th Army of the Japanese Army in Wuhan, and they were in front of the so-called "combat area" of the Japanese army, so combat operations were relatively frequent.

According to the terrain of the theater and the deployment of the Japanese army, and summing up the combat experience of the First Battle of Changsha and the Battle of Shanggao, the Ninth Theater judged the direction of the Japanese army's attack: on the northern Jiangxi side, one was from De'an and Anyi to Wuning, Xiushui, and Tonggu, and the other was from Nanchang to Gao'an, Shanggao, and Wanzai, or from Nanchang to Xingan and Ji'an; In southern Hunan, it may be directed south from Chongyang, Tongshan and Tongcheng to Pingjiang and Liuyang; In northern Hunan province, it will go south from the areas on both sides of the Guangdong-Hanzhou Railway to Changsha. Among the above directions, Xiangbei should be the main direction, and the others are the direction of response or containment. Accordingly, the Ninth Theater deployed the main force in northern Hunan and used the Xinqiang River, Miluo River (Mishui), Laodao River, and Liuyang River in the depth of this direction to build multi-layered positions, strengthen the resilience of defense, and control the mobile troops in the mountains of Mufu Mountain and Lianyun Mountain on the east side, so as to flank and attack the Japanese army.

The Ninth Theater of Operations has drawn up a plan for counterattack operations. Its policy is:

On the side of northern Jiangxi and southern Hunan, against the enemy who is not the main attack, we will strive to flank it in the areas north of Chongren and Xingan, east of Yichun, Wanzai, Tonggu, Xiushui and north of Xiushui, and break them individually; On the northern Hunan side, if the enemy attacked Changsha with the main force from Yanglin Street, Changle Street, Fulin Pudao Road, and the areas on both sides of the Guangdong-Hanzhou Railway, he would lure the enemy to the south of the Miluo River and on both sides of the Laodao River, counterattack and annihilate him. The main guiding principle is to apply the tactics of luring the enemy into depth, counterattacking and annihilating the enemy.

Before this battle, the regular troops under the jurisdiction of the Ninth Theater consisted of 3 group armies, 11 armies, and 30 divisions, as well as a number of guerrilla columns. The General Headquarters of the 30th Army was located in Xiushui. The 78th Army to which it belongs: served as the garrison of the line of Guanyin Pavilion and Tanbu; The main forces of the 72nd Army were assembled in the north and south areas of Sandu.

The General Headquarters of the 19th Army was located in Kamigao. The new 3rd Army: served as the front-line garrison of Jing'an and Fengxin; 74th Army: Assembled in Xinyu and Fenyi areas for training; Reserve 5th Division: serve as the first-line garrison of Shixia Street and Wenzhen; Jiangxi Security Column: Served as a garrison on the south bank of the Jinjiang River.

Hunan-Hubei-Jiangxi Border Region Advance Army: The main force was deployed in the area between Xianning and Ruichang as guerrillas.

The headquarters of the commander of the 9th theater is located in Changsha.

In early September, the Japanese 6th Division, in order to cover the assembly of the main force and remove the flank and rear threat of the river crossing area, carried out a sweeping operation to the 4th Army's advance stronghold on the north bank of the Xinqiang River, and launched a full-scale attack on September 18.

From September 8th to 9th, the main force of the 6th Division of the Japanese Army attacked the eastern side of Dayun Mountain, although the defenders resisted hard, but because the Japanese army was superior in strength and firepower, the blockade was ineffective, and they abandoned Dayun Mountain.

On the 10th, the main force of the 6th Division believed that it had completed the sweeping mission, withdrew from Dayun Mountain, and assembled in the direction of Taolin, while its 13th Wing was blocked by the Chinese 102nd Division and the 1st Division of the 59th Division near Gantian and Tuanshan slopes, and fell into a bitter battle.

On the same day, the Chinese 58th Division regained the Dayunshan position, and the 60th Division of the 37th Army, which reinforced Dayunshan, had also arrived on the battlefield, and the 27th Army then ordered the newly formed 10th, 59th, and 60th Divisions to surround and annihilate the Japanese troops in front of them, and the attack was scheduled to begin at dawn the next day.

On the 11th, when these three divisions were fighting fiercely with the 13th Wing, the Chongsong Detachment of the 40th Division of the Japanese Army, which had advanced westward from Xianning, rushed to Gantian and received the 13th Wing to withdraw to Straw Shoe Ridge.

From the 12th to the 14th, the Chinese army continued to attack the Chongsong detachment, and the two sides fought each other in a narrow area on the slopes of Gantian and Tuanshan, with heavy casualties.

At this time, the Ninth Theater had not yet determined the Japanese army's intention to attack Changsha, and still believed that the Japanese army's attack on Gantian north of Yanglin Street was a cover for its retreat. For example, Xue Yue sent a telegram to Chiang Kai-shek on the 14th: The Japanese army "swept our Dayun Mountain, and then crossed the Xinqiang River to the south to disturb it." After judging that the enemy was on the high ground, the 33rd Division took the advance as a retreat."

On the 15th, the Japanese army was reinforced by the Araki detachment, which had just arrived from northern Jiangxi, and the battle was extremely fierce. At this time, the Ninth Theater found that the Japanese army had more than four divisions and regiments gathered in northern Hunan Province, and found that the Japanese army was about to launch a large-scale attack on Changsha, so it ordered the main force of the 27th Army to move south of the Xinqiang River, and the battle of Dayun Mountain came to an end.

On September 17, all the Japanese troops transferred from various places to northern Hunan had been assembled and entered the position of starting for the offensive. Having learned the lesson of the dispersion of forces during the First Battle of Changsha, Anan Weiki deployed the attacking forces in a narrow front in the hope of making a breakthrough in depth. Forty-four battalions and 322 artillery pieces and mortars were deployed on a frontage only 20 kilometres north of the New Wall River. Only the 63rd Brigade of the 14th Brigade of the Independent Mixed Brigade was sent to the south of the Xiangjiang River by boat, attacking Qingshan and Yingtian, covering their right flank, and responding to the frontal main force.

At dawn on September 18, the Japanese launched an attack on all fronts.

The Japanese forced the crossing of the Xinqiang River with the support of artillery, aviation fire and combat vehicles. The divisions of the 4th Army relied on their established positions to resist the Japanese army. The 102nd Division fought head-on against the concentrated attacks of the Japanese 4th, 3rd, and 6th Divisions, and the fighting was particularly fierce. A few hours later, the Japanese successfully crossed the river and broke through the first line of the defenders. The Japanese 3rd and 4th Divisions and the Hayabuchi Detachment quickly advanced southward along the areas on both sides of the Guangdong-Hanzhou Railway, and the 3rd Division made a detour to the flank of the 4th Army. The Japanese Hirano detachment also took naval ships to advance along the east side of Dongting Lake to land near Qingshan at the mouth of the Xiangjiang River, and coordinated with the main force to attack the defending 99th Army on this side.

By 16 o'clock, the second line of positions of the 4th Army was broken through by the Japanese again.

On September 20, the Military Commission ordered the Ninth Theater to hold on to the existing positions on both sides of the Xiangjiang River and south of the Miluo River, strengthen resistance, maintain the main force on the outer flank, and strive to attack the enemy's flank. The 3rd and 5th Theaters were ordered to take advantage of the situation to attack the enemy in front of them, so as to prepare for the operations in the 9th Theater. At the same time, the Sixth Theater of Operations actively attacked the Japanese army in Jingzhou and Yichang, and recovered Yichang.

However, the telegram sent by the Ninth Theater to all group armies and armies on September 18 was stolen and deciphered by the Japanese special intelligence department and sent to the 11th Army. When the Ninth Theater received information that the Ninth Theater was defending the existing positions on the Miluo River with four divisions and placing the main force on the Wengjiang River and other places in the east of the battlefield to flank the Japanese army, it immediately changed its original deployment, ordered the 3rd and 4th Divisions to turn to the area east of the Hukou and Wengjiang rivers one by one, and caused the 40th and 6th Divisions to make a detour from the mountains to the east to form an encirclement posture for the 37th, 26th, and 10th armies of China. Annihilation.

On September 20, the 4th, 3rd, and 6th Divisions of the Japanese Army and the Zaoyuan Detachment forcibly crossed the Miluo River from Luogongqiao, Xinshi, Whetstone, Hukou and other river crossing points, breaking through the forward position of the 37th Army. The 40th Division of the Japanese Army was attached to the Araki Detachment, and after repelling the flank attack of the 4th Army, the Liujiangteng Detachment covered the supply line, and the main force turned to the area east of Xinguanqiao and Wengjiang, and was scheduled to make a roundabout southward journey through Pingjiang.

Not only did the Ninth Theater's attempt to fight a decisive battle with the Japanese army on both sides of the Miluo River and destroy the main force of the Japanese army not only failed to materialize, but the various armies that were serving as garrisons in this direction were broken by the Japanese army and suffered heavy losses.

The 4th, 3rd, 6th, and 40th Divisions, the Hayabuchi Detachment, and the Araki Detachment broke through the defenses of the Chinese 37th, 26th, and 10th Armies south of the Miluo River, and then advanced southward, and arrived at the north bank of the Laodao River around September 25, approaching Changsha.

However, the telegrams of the Ninth Theater were repeatedly stolen and deciphered by the Japanese army's special intelligence services. The Japanese 11th Army was aware of all the actions of the Chinese army. The commander of the 11th Army, Anan, constantly adjusted his deployment according to the changing situation of the Chinese army, so that the Chinese army was restrained everywhere on the battlefield, suffered huge losses, and the positions were frequently broken through by the Japanese army, and they retreated one after another.

On the evening of September 25, the headquarters of the Commander of the Ninth Theater was forced to withdraw from Changsha to Xiangtan.

The 11th Army was the only field army in the Japanese army invading China that mainly focused on mobile combat missions, and since the fall of Wuhan, the Japanese army launched many attacks on the frontal battlefield, except for the Battle of Guinan and the Battle of Zhongtiao Mountain, were all launched by it. China's military intelligence should be more sensitive and closely monitoring its movements.

In order to prepare for this battle, the 11th Army began to transfer troops from western Hubei, southern Hunan, and northern Jiangxi to northern Hunan from mid-August. For as long as one month, the strategic intelligence department of the Military Commission, the campaign intelligence department of the third, fifth, sixth, and ninth theaters, and the tactical intelligence departments of various units that had face-to-face contact with the Japanese army were unaware of such a large-scale troop movement.

Due to the unclear situation, the Ninth Theater had no way to carry out the battle and had no time to make targeted preparations, and its front-line garrison troops, the 4th Army and the 58th Army, were even attracted by the Japanese army and stuck to Dayun Mountain. The paralysis and laxity of military intelligence directly led to passivity on the battlefield and military defeat.

The Japanese army succeeded in concealing the battle attempt and giving full play to the suddenness of the battle, while the Ninth Theater lost the opportunity at the first step of the battle, rushed to deal with it, and lost every step in the face of the Japanese lightning-like attack.

In order to salvage the declining situation of the Chinese army at the beginning of the Battle of Changsha, the Central Military Commission repeatedly telegraphed orders on September 20 and thereafter, ordering the Third, Fifth, and Sixth Theaters to launch a wide range of attacks and harassment activities against the Japanese troops in front of them, indirectly supporting the operations in the Ninth Theater.

Theatre III was ordered to begin a full-scale assault on 23 September. Its 100th Army frequently launched attacks on the strongholds of the 34th Division of the Japanese Army around Nanchang, and even advanced to the suburbs of Niuhang, Lehua and Nanchang, captured Louqian City and Huangxidu, and repelled many counterattacks by the Japanese army; The 23rd Group Army repeatedly attacked Hukou, Pengze, Madang, Guichi, Fanchang and other key points along the river held by the Japanese 116th Division, and repeatedly broke through to the river to lay mines and destroy the enemy's water communication lines.

Xiao Xiong's anti-enemy special force in northern Jiangxi also received an order from the commander's headquarters of the Ninth Theater, asking them to assist in the military operations of the Third Theater, to attack the strongholds, docks, warehouses, and road traffic of the Japanese army in the area under its jurisdiction, to disrupt the enemy's rear, to disrupt the enemy's deployment as much as possible, to hold back the Japanese army in northern Jiangxi, and to support the Second Battle of Changsha.

In fact, on the eve of the Second Battle of Changsha, Xiao Xiong's special forces had already discovered the enemy's abnormal movements and reported the reconnaissance to the Ninth War Zone, but it did not attract the attention of the superiors.