In the summer of 1948, the nationalists in Shandong was forced on the defensive after military setbacks by withdrawing into major cities such as Jinan and Qingdao while stationing some forces along the Tianjin-Pukou Railway to secure the communication / transportation line. The communists decided to have the communists units in Shandong to annihilate enemy gradually in the region from Tai'an in the north to Xue City in the south, thus threatening Xuzhou by linking up with the communists in the southwestern Shandong. The success of this campaign would assist another communist summer offensive, the Eastern Henan Campaign. To carry out the plan, the local communists in Shandong decided to first take Tai'an and its surrounding regions in the north and south, thus cutting off the link between Yanzhou and Jinan, and then take the isolated Yanzhou and ambush any nationalist reinforcement to the town.
Order of battle
Defenders: nationalist order of battle:
*The 10th Pacification Zone Command
*The Reorganized 12th Army
**The Reorganized 12th
*The 2nd Division
*The Reorganized 25th Division
*The Reorganized 84th Division
*Numerous local security divisions
Attackers: communist order of battle:
*The 7th Column
*The 9th Column
*The 13th Column
*Units from the Central Shandong Military District
*Units from the Southern Shandong Military District
On May 29, 1948, the communist Shandong Corps launched the campaign against the nationalist targets along the central section of the Tianjin-Pukou Railway, and the nationalist 155th Brigade of the Reorganized 84th Division guarding Tai'an was forced to abandon the city and retreated northward. The enemy was then able to expand their victory from Tai'an northward and southward, and by June 20, 1948, other cities and towns including Great Wen Mouth , Qufu and Zou City had fallen into the enemy hands. Meanwhile, Yanzhou, was besieged by the communist 7th Column. By June 25, 1948, the nationalist stronghold outside the town, Four Pass had fallen into the enemy hands.
In order to reinforce Yanzhou, the nationalist Reorganzied 25th Division stationed in northern Jiangsu was sent from Xuzhou along the Tianjin-Pukou Railway, and its advanced guard had reached the region of Border River north of Tengzhou by June 28, 1948. The communists decided to ambush the nationalist reinforcement by deploying the 9th Column and the 13th Column, while the communist 7th Column was order to stop its assault on Yanzhou and redeployed to assist the 9th and the 13th Column. As the communists laid their trap, the nationalists changed their priority. The nationalist force in Sui county and Qi county in eastern Henan under the command of the corps commander Qu Shounian was besieged by the enemy and the situation was far more desperate than Yanzhou, so the nationalist Reorganized 25th Division was redeployed to Shangqiu by rail to reinforce the battlefield in eastern Henan, and thus inadvertently avoided the ambush set up by the enemy.
The nationalist redeployment had left strategically important town, Yanzhou dangerously undermanned: the nationalist garrion of the town only had the Reorganized 12th Army and security divisions totaling 28,000 troops. The nationalists were betting on the terrain that favored the defenders to secure the city: as an important junction of the Tianjin-Pukou Railway, nationalist reinfocement from other places could readily reach the town via railroad, and located on the western bank of Si River, the surrounding regions of the town was wide open with little cover for the would be attackers, and there were semi-permanent fortifications both inside and outside the town. The battle and the consequent fall of the town into the enemy hands proved that these natural geographical advantages could not be counted on. The communists decided to attack Yanzhou again by concentrating a total of fifteen brigades from Shandong Corps and local units to take the town and annihilate nationalist reinforcement. The communist 7th Column, 13th Column and units from Central Shandong Military District were tasked to attack the town, while the communist 9th Column was deployed to the north of Yanzhou, and the communist units from southern Shandong Military District was deployed to the south of Yanzhou to ambush nationalist reinforcements. The communist Column was deployed to the east of Jinan to prevent nationalists stationed in the city from reinforce Yanzhou.
On July 1, 1948, the communist Shandong Corps besieged Yanzhou again. The communist 7th Column and the bulk of the communist 13th Column were tasked with major responsibility of attacking eastward from the west, with emphasis on the Old Western Gate and the New Western Gate . The communist units of the Central Shandong Military District and a portion of the communist 13th Column were deployed to the northeast and east of the town to assist the main attacking force. At 5:00 p.m. on July 12, 1948, the assault on the city began. The intense fire destroyed city wall along the Old and New Western Gates sections, and associated defensive positions. Under the cover of the shelling of mountain guns, the attacking infantry breached the defense and penetrated into the city at 8:30 p.m. After a failed attempt to to the east, the nationalist garrion was completely annihilated, with the nationalist of the region and the commander of the Reorganized 12th Army, Huo Shouyi captured alive. The town was declared secured by the communist forces at 6:00 p.m. on July 13, 1948 after the mop up operation was completed.
As Yanzhou was besieged once again, the nationalist Reorganized 84th Division and the 2nd Division went out to reinforce their comrades-in-arms, but due to the fear of being ambushed, the progress was extremely slow. When the advanced guard of the nationalist reinforcement had cross Wen River and reached the town of Taiping on July 13, 1948, the news of the fall of Yanzhou had reached the nationalists, who immediately withdrew northward. However, the retreating nationalists were caught up by the pursuing communist forces and the nationalist Reorganized 84th Division was badly mauled by the communist 9th Column, losing over 10,000 troops, including most of its 161st Brigade. This last battle concluded the campaign.
The nationalists suffered more than 63,000 casualties in their defeat, and a dozen cities / towns including Qufu, , Tai'an, Zou County, and Yanzhou had fallen into the enemy hands. The nationalist garrison in Jinan was further isolated and the enemy succeeded in combining the previously separated communist bases in central and southern Shandong and western Shandong into a new one of much greater size. The fall of the strategically important railroad junction Yanzhou also meant that both Xuzhou in the south and Jinan in the north controlled by the nationalists were threatened by the enemy, and communist victory also helped their Eastern Henan Campaign by tying down the nationalists forces in Shandong.