The Battle of Siping (Chinese: 四平保卫战) was a battle between the Nationalists and the Chinese Communist Party (CCP) for the control of Siping in 1946 during the Chinese Civil War. This campaign was characterized by the fact that the supreme commanders of both sides had overestimated their strength and set unrealistic goals, but in both cases, the frontline commanders on both sides averted the potential catastrophes by convincing their respective supreme commanders to change their original decisions.

After the defeat of Jinjiatun Campaign, the nationalists resumed their offensive with vengeance. In a short period of just two days, the nationalists were able to regroup and re-supply completely, and continued their push toward Siping. Chiang Kai-shek was determined to capture Changchun after taking Siping, and Mao Zedong was equally determined to hold Siping to the end and prevent the nationalists from capturing both Siping and Changchun. Both sides realized the upcoming campaign would be a difficult one and both sides placed one of their best field commanders in charge: Du Yuming for the nationalists and Lin Biao for the CCP.

Attackers: nationalist order of battle:

Defenders: CCP order of battle:

Under Mao Zedong's strategy, the communists were determined to hold Siping to the end. In order to fortify the city, everyone was mobilized to build bunkers inside the city, while food, ammunition and other supplies were stacked. Lin Biao and Mao Zedong had personally inspected communist fortifications at important defensive positions such as Pagoda Mountain (Tazishan, 塔子山) and Three Lines of Groves (Sandaolinzi, 三道林子) with Peng Zhen in preparation for a prolonged campaign. Lin Biao also held a conference at Lishu County to plan the strategy of the defense: To better coordinate the defense of Siping, the communist formed an urban defense command inside the city headed by the Ma Renxing [zh], the commander of the communist 1st Brigade, while the general headquarters retreated to the suburb at Lishu County. In order to boost the morale of defenders, a newspaper titled "Self Defense Newspaper" was created with Chen Yi [zh], the deputy director of the political directorate of the communist general headquarters as the chief editor. The communist decided to deploy only two regiments in the city to check the nationalist attacks while the bulk of their force would be deployed in the rear, in the region between Siping and Lishu County and the region between Siping and Bamiancheng [zh]. Once the attacking nationalists were checked by the defensive force of the city in fortification, the communists would then concentrate their force to strike the weakest nationalist 71st Army.

On April 17, 1946, Nationalist frontline commander Zheng Dongguo and his deputy Liang Huasheng (梁华盛) moved their headquarters to Shuangmiaozi [zh] and ordered an immediate attack on the city. On April 18, the railways reaching the city was successfully severed. Two regiments of the 30th Division of the nationalist 71st Army under the command of Chen Mingren attacked the enemy positions from the south from Haifeng Village (Haifeng Tun, 海丰屯), Pobozi (泊脖子), and Duck Lake Pao (Ya Hu Pao, 鸭湖泡) regions, but were beaten back three times consecutively. After the initial setback, Zheng Dongguo held a military conference on April 19. The nationalist army and divisional commanders attending the conference concluded that the frontal attack on the strongly defended enemy positions was impossible, and attacks from flanks or other weak points must be selected instead in order to achieve a successful breakthrough. The railway junctions that provided the link between the 3rd Battalion of the communist 1st Regiment and the communist 56th Regiment appeared to be a good point for the breakthrough. After the conference, under heavy artillery cover, the 30th Division of the nationalist New 1st Army launched its offensive on the junction of the two communist units, and the nationalists had successfully taken the enemy position as expected. The loss of the position at the railway junction signaled that the defensive force inside the city must be strengthened and Lin Biao immediately did so, and informed the defenders in the city.

The arrival of the reinforcements greatly boosted the morale of the defenders and the advance guard of the 21st Regiment of the 7th Brigade of the communist Western Manchurian 3rd Division launched a counterassault on the nationalists with the help of other communist units, and successfully took back the positions at railway junction previously lost on the same afternoon, while inflicting heavy casualties on the nationalists in the process, and the heavy casualties stopped the offensive of the nationalist 30th Division completely. After the struggle for Siping had begun, both Chiang Kai-shek and Mao Zedong in their distant headquarters were concerned about the development and both frequently inquired the progress on the battlefield. Chiang was determined to take Changchun and thus Siping must be taken first to open the path for Changchun, while Mao felt that Siping must be held at all cost and on April 22, Mao telegraphed Lin Biao to order him to hold on and wait for the campaign to turn for the better. From April 18, through April 26, 3 divisions from the nationalist New 1st Army and the 71st Army took turns to assault the enemy positions, but were all beaten back by the enemy in favorable terrain. By the evening of April 26, 1946, heavy casualties forced the offensive of the nationalist 71st Army to a complete stop, while that of the nationalist New 1st Army was reduced to skirmishes.

After failing to make significant progress, the nationalists resorted to artillery to shell the enemy, but this resulted in a disastrous failure. The terrain favored the defenders in that there were relatively few artillery positions outside the city for shelling the city, and defenders were well aware these positions. The nationalists enjoyed numerical superiorities in artillery so these positions were jammed with nationalist batteries. The enemy defending the city, on the other hand, had fewer artilleries and thus was forced to move around whenever and wherever they were needed, and such frequent and rapid movement to the next new position where artillery support was needed helped the enemy artilleries from being shelled by the nationalist counter-artillery fire. In contrast, nationalist artillery was the first to fire for most of the time, but after firing, they were not able to move around due to limited positions available and the high concentration of batteries deployed in the few available positions. As a result, the nationalist batteries became victims of enemy counter-artillery fire and suffered great loss. When nationalists were forced to withdraw their batteries from the few available artillery positions to avoid losses, the enemy was out of range. As a result, the attacking nationalists lost the artillery duel. Mao was happy that the nationalist attack was beaten back again, and on April 27, 1946, telegraphed Lin Biao to praise him and his troop, and asked Lin Biao to deploy one or two more regiments to develop Siping into Madrid in the East.