the nationalist futile attempt to counterattack and retake these strongholds were beaten back for more than thirty times. Afterward, the enemy approached the outer city of Linfen, the Eastern Pass (Dong Guan, 东关), which was the barrier for Linfen, and the nationalists desperately attempted to hold on this critical defensive stronghold. From March 23, 1948 – March 27, 1948, the nationalist defenders twice successfully beaten back the attacks on Eastern Pass (Dong Guan, 东关) by the communist 13th Column. On April 1, 1948, the enemy adjusted tactic and the communist 37th Brigade of the 13th Column attacked from southeast and the communist 23rd Brigade of the 8th Column attacked from northeast simultaneously, while the 4 tunnels were dug toward the city wall. On April 10, 1948, three of the four tunnels were filled with explosives and detonated simultaneously, succeeding in collapsing the city wall of the Eastern Pass (Dong Guan, 东关) section, and attacking communist 37th Brigade of the 13th Column and the communist 23rd Brigade of the 8th Column were able to swiftly taking the Eastern Pass (Dong Guan, 东关), the outer city of Linfen, badly mauling the local defenders, the nationalist 66th Division. Second stage On April 16, 1948, the battle mostly had switched to underground when the communist 8th Column and Taiyue (太岳) Military District at eastern outskirt of Linfen and the 13th Column at southern outskirt of Linfen begun to dig 15 tunnels toward the city wall and an additional 40+ tunnels for cover. Taking the lesson learned from the loss of Eastern Pass (Dong Guan, 东关), the defenders also begun to dig tunnels to counter the underground threat. In addition, under the cover of shelling with incendiary rounds and gas attacks, the nationalist 30th Brigade counterattacked the enemy with air cover. Although the nationalist counterattack was beaten back the enemy, and the nationalists did succeed in destroying most of the enemy tunnels. On May 1, 1948, the Xu Xiangqian changed their tactic by deploying the communist 13th Column to the east of the city to assist the communist 8th Column to attack the city, while the 22nd Brigade of the communist 8th Column and the 39th Brigade of the communist 13th Column were deployed to assist the communist regiment of the Taiyue (太岳) Military District on the western bank of the Fen River to blockade the escape route of the fleeing enemy. On May 16,