The Eighth Route Army completely occupied Shenyang on the evening of 27 March, Yamada Otozo arrived in Changchun on the morning of 28 March, and Liu Yimin held a meeting of the Northeast Bureau on the evening of 29 March.

Siping Street, the name of Siping Street, is located in the central plain of Northeast China, at the intersection of the three railways of Zhongchang, Sitao and Simei, and is the throat of the east, west, north and south. Before the Russo-Japanese War, Siping had just over 7,000 people and was just a small market town. Due to the Russians opening a commercial port and building a railway here, Siping became a fur and grain distribution center in the areas of Taonan, Tao'an and Liaohe, and commerce gradually prospered, and the population soon increased to 30,000. After the Russo-Japanese War, the Japanese occupied Siping, commerce became more developed and prosperous, and the population increased from 30,000 to 60,000. After the "918" incident, the puppet Manchurian district was set up in Siping Province, which was the provincial capital, the population increased to 110,000, and the urban area was 9 miles long from north to south and 8 miles from east to west, with an area of about 20 square kilometers, becoming a modern medium-sized city.

The railway from Changchun to Shenyang passes through the middle of Siping City, dividing the city into two parts: Daodong and Daoxi.

Siping's military status is important, but that is said when the two sides are fighting. Before the September 18 Incident, the Japanese army had only one squadron and one gendarmerie detachment in Siping to protect the so-called Manchurian Railway annex. After the 918 Incident, Siping was only seen between Shenyang and Changchun, that is, between Mukden and Xinjing in the eyes of the Japanese puppet army, and belonged to the hinterland of the Japanese puppet rule, mainly with the gendarmerie to maintain law and order. The garrison was just a brigade. When Siping Province was established and it was necessary to rule the Siping region, the Japanese army stationed an independent garrison here, that is, the independent third garrison of the Kwantung Defense Army, which was established on the eve of the Japanese-Soviet War.

Umezu Mijiro's deployment of troops in Tohoku before his death was actually heavy on the outside and light on the inside. The focus of defense remained on the USSR. Therefore, he deployed the Third, Fourth, Fifth, Sixth, and Twentieth Armies in Mongolia and the Far East, or in the northern and eastern regions of Heilong, and the Jilin region was mainly garrisoned by troops directly under the direct jurisdiction of the Kwantung Army, while Liaoning was all garrisoned by the Kwantung Defense Army. The puppet Manchu army was stationed according to the original six military administrative regions.

This kind of deployment now seems to be simply sending Liaoning to the Northeast People's Anti-Japanese Democratic Alliance Army. However, Umezu Mijiro's initial deployment was made after careful consideration and approval by the Japanese army headquarters, because the Japanese were bent on completely Japaneseizing Mongolia and the Far East. It will not work if you do not garrison heavy troops. As for the hinterland of Manchuria, the Japanese believed that after so many years of rule, they had already surrendered, and that it would be enough for the Kwantung Defense Army and the troops directly under the Kwantung Army and the puppet Manchurian Defense Army to be stationed.

Umezu Mijiro, the demons of the Japanese army's base camp, who would have thought that Liu Yimin would dare to land in the Northeast and attack the hinterland of the Northeast?

Siping Province was carved out from Fengtian Province and Jilin Province, and there were nine counties in one city, including Siping Street, Lishu County, Kaiyuan County, Xifeng County, Shuangliao County, Hailong County, Dongfeng County, Xi'an County, Changtu County, and Changling County. It is all up to the gendarmerie and the police to maintain their rule.

At this time, the 3rd Independent Garrison of the Japanese Army in the Siping area had already received information that Liu Yimin's troops had captured Shenyang, and had begun to shrink its troops. Prepare to stick to Siping. When the news of the fall of Kaiyuan came, the Japanese Army's Independent Third Garrison, which had not yet completed the shrinkage of its forces, urgently asked for help from the Kwantung Army Headquarters, and began an emergency mobilization in Siping Castle again, arming all the Japanese puppet officials in Siping Castle and preparing to participate in the Siping garrison battle.

When Gao Yuan arrived at the Siping front line by train after attending the meeting of the Northeast Bureau, the armored regiment and the 1st Brigade were already making combat preparations for the capture of Siping.

Gao Yuan didn't know that during the Liberation War in history, Siping was the sad place of the Northeast Field Army twice. The first was the Battle of Siping, which took place in May 1946, and the chairman strictly ordered Lin Biao to defend Siping. The slogan put forward was "turning Siping into Madrid," and the purpose was to gather the main forces to fight in Siping, thoroughly thwart the offensive of the Kuomintang army in the northeast, force it to return to the negotiating table, and form a strategic situation in the northeast in which the Kuomintang occupies the south of Shenyang and our party occupies Changchun and Harbin. Outcome. After a month of fierce fighting, after the loss of the Tazishan position, the commanding heights in the east of Siping, Lin Biao decisively ordered the entire line to retreat. With this withdrawal, our army retreated all the way north and crossed the Songhua River, and the Kuomintang won a phased victory in the offensive operations in the northeast. Fortunately, Chiang Kai-shek ordered the pursuit to the north of the Songhua River to be stopped, otherwise the Northeast Field Army would have been in a predicament of poor communication and command failure, and the situation would have been even more difficult. The defeat in the first battle to defend Siping was actually a defeat in the strategy of economic strategy in the northeast, which proved that the idea of competing with the Kuomintang for big cities and railway lines under the conditions of the time was unrealistic. The second was the Siping Battle, which took place a year later in June 1947. At that time, the Northeast Field Army had grown to 400,000 and had just won the summer offensive victory. Under the command of Chen Mingren, the Kuomintang army Chen Mingren used the reinforced concrete structure buildings in Siping City to repair the fortifications, and the buildings were figured out by tunnels, and the electric lights were assumed in the tunnels, turning the entire Siping City into a reinforced concrete fortress. After our army launched an attack, it broke through the city defense on the same day and started a battle for the city with the Kuomintang army. As a result, due to the massive reinforcements of the Kuomintang army from the north and south, our army had to withdraw from the battle again with tears at the expense of heavy sacrifices and the capture of two-thirds of the city. In these two battles of Siping, our army did not achieve the purpose of the campaign.

Gao Yuan is not a traverser, so he naturally does not know the sorrow of the two Siping battles of the Northeast Field Army. However, he was deeply influenced by Liu Yimin's military thoughts, and knew that the true meaning of the city attack was to concentrate all forces to break the city in one fell swoop. Moreover, the battle plan issued by the General Staff Office before departure was clearly written, with a unit to outflank Siping, cut off the connection between Siping and the direction of Gongzhuling, concentrate the armored brigade, the first brigade, the second brigade and all the artillery fire that could be used, and attack the city in one fell swoop.

The third garrison of the Japanese army did not have as much time as Chen Mingren had to defend Siping, they were urgently mobilized and urgently established a defensive line, and they were not even able to establish a defensive line at the commanding heights of Tazi Mountain, which was only more than ten kilometers away from Siping City. Because of their limited strength, no matter how urgently they gathered their troops, it would be impossible for all the troops stationed in the counties to rush back, plus one brigade originally stationed in Siping, at this time there were only two or three main infantry brigades in Siping City, and the rest were military police, police, cadres of Japanese puppet organs, and soldiers in the township. With such a small number of troops, it is not enough to defend Siping City, and what do you say about going to Tazishan and other peripheral points to give up your position!

After receiving the report of the Siping defenders, the commander of the Kwantung Army, Yamada Oto, ordered the chief of staff, Muto Akira, to call back to the Siping defenders, asking them to rely on the city defense to defend and delay Liu Yimin's troops for two days before retreating in the direction of Gongzhuling.

Yamada Otozo originally wanted to order the Siping defenders to withdraw to Gongzhuling immediately, but considering that it would take time for the main force of the Kwantung Army to assemble, Liu Yimin's troops could not be allowed to attack Changchun so quickly, and they had to be blocked and delayed along the way, so it was decided that the Siping defenders would evacuate after holding on. The reason why the Siping defenders were ordered to hold on for two days was to consider that the strength of the Siping garrisons was too weak and it was impossible to hold on for a long time. At the same time, relying on the fortification of the city, there should be no problem in two days. If Siping is held for two days, and the direction of Gongzhuling is held for three to five days, by the time Liu Yimin attacks the city of Changchun, the main force of the Kwantung Army can basically complete the assembly. When the time comes, Changchun City will be used as the fulcrum of defense, attracting Liu Yimin's forces to attack and annihilate it in one fell swoop!

Liu Yimin wanted to besiege Changchun as bait and encircle the point to send reinforcements, and Yamada Yisan wanted to use Changchun as bait to annihilate the main force of the Northeast People's Anti-Japanese Democratic Alliance Army in the next battle in Changchun City, and the two commanders thought of going together. It's up to who's plan to come true.

Chief of Staff Muto Akira knew that Liu Yimin's firepower was fierce, and the Siping defenders were alone, and it was impossible to hold out for too long. After thinking about it for a while, out of the idea of preserving strength, Muto Akira suggested that Yamada Otozo revise the order and change it to the Sihei defenders to hold on for a day after the battle began, and then retreat in the direction of Princess Ridge.

By this time, there was an air reconnaissance and a report from the Siping defenders, and Yamada Otozo had already seen it in his heart, Liu Yimin had a lot of appetite, and he wanted to take Changchun directly. It just so happened that it was annihilated in one fell swoop under Changchun City, but the main force of the Kwantung Army was stationed in various places and was being assembled, and the three most elite divisions reinforced Shandong to fight were also assembling towards Qingdao, and he needed time.

After thinking about it, Yamada Otozo said to Muto Akira: "In this case, the pressure in the direction of Princess Ridge will be great. Gongzhuling is the last line of defense in Changchun, and we must hold on for more than three days, otherwise, the main force of the Kwantung Army will not be able to assemble, and our plan may fail. ”

Muto Zhang came to be confident at this time, and said: "The Fourth Flying Group will arrive soon, it is best for Liu Yimin to kill under Changchun City, there are directly subordinate troops gathered here, we can use powerful aviation firepower to kill and injure Liu Yimin's troops in large numbers, and create conditions for the complete encirclement and annihilation of Liu Yimin's troops." ”

In this way, the fate of the Japanese army in Siping was doomed in the foresight of the commanders of the Kwantung Army, Yamada Otsuzo and Muto Akira.

In Liu Yimin's thoughts, the enemies of Kaiyuan, Siping, and Gongzhuling have all become corpses or prisoners. Because he knew in his heart that the Japanese army would not have time to build a strong defensive line, let alone gather and gather troops. After our army occupied Shenyang, the Kwantung Army headquarters did not dare to send a large number of troops from Changchun to reinforce Siping and Gongzhuling, because they were afraid that after the reinforcements were wiped out in Siping and Gongzhuling, Changchun would become an empty city. Therefore, Liu Yimin sat firmly in Shenyang, just urging the army to attack on all fronts, and let them do their best on the plateau.