Bright Sword: Construction starts from southeastern Shanxi

Japan comprehensively strengthened its economic blockade, military offensive and political inducement to China, which made the War of Resistance even more difficult. Some people in the Kuomintang became more shaken, and the crisis of compromise and surrender became unprecedentedly serious.[10] [4]

In order to overcome this serious crisis, the CPC Central Committee issued a Declaration on the Current Situation on the Third Anniversary of the Anti-Japanese War on July 7, 1940, stating that Japan "is attempting to use methods such as blocking our international transportation lines, attacking us head-on, and conducting aerial bombings to increase pressure and aggravate difficulties in order to achieve its goal of splitting China internally and forcing China to surrender." "Now is a period of unprecedented danger of surrender and unprecedented difficulty in the war of resistance for China." It called on "the whole country to intensify its unity and overcome this danger and difficulty." [11] Therefore, the Eighth Route Army Headquarters decided to implement the well-planned plan of destroying the Zhengtai Road, attack the enemy's rear transportation lines, and deal a powerful blow to the enemy's North China Front Army, crushing Japan's intentions and helping the national situation to improve.

On July 22, 1940, the Eighth Route Army Headquarters issued a "Battle Preparation Order" to the Shanxi-Chahar-Hebei Military Region and the 129th and 120th Divisions, and simultaneously reported it to the Central Military Commission of the Communist Party of China. After analyzing the evolving domestic and international situation, the order stipulated that no fewer than 22 regiments should be directly involved in the Zhengda Line operations. It mandated that the Shanxi-Chahar-Hebei Military Region send 10 regiments, the 129th Division send 8 regiments, and the 120th Division send 4-6 regiments. The majority of the headquarters artillery regiment and part of the engineering corps would also participate. Troops for supporting operations on other railways were to be arranged by each region independently.

On August 8, 1940, the Eighth Route Army Headquarters issued the "Campaign Operation Order", which determined the battle deployment and combat area. [13] The Jin-Cha-Ji Military Region used 10 main force regiments to destroy the Zhengtai Railway from Pingding (excluding) to Shijiazhuang, focusing on destroying Niangziguan and Pingding sections. Sufficient troops should be dispatched to attack the Beining, Jinpu, Deshi, Cangshi, Pinghan and other railways around the border area to block the enemy's possible reinforcements to the Zhengtai Railway. [4] The 129th Division used 8 main force regiments, plus a battalion of the headquarters artillery regiment, to destroy the Pingding (including) to Yuci section, focusing on destroying the Yangquan and Zhangjing sections. Sufficient troops should be dispatched to attack the Pinghan, Deshi, Tongpu, Baijin Railways and Handa and Lintun Highways around the base area. Strong troops should be sent to actively carry out activities on the Pingliao Highway. [4] The 120th Division should attack the Tongpu Railway and Fenli Highway north of Pingyao; the deployment for attacking the Tongpu Railway should be to place heavy troops in the north and south of Yangqu to prevent the enemy from reinforcing the Zhengtai Road, and strive to advance about two regiments to the north and south of Yuci to cooperate with the 129th Division in the battle; troops should be dispatched to actively attack various enemy strongholds and transportation lines in the hinterland of northwest Shanxi. [4] The headquarters special forces regiment assembled in Xialiang and Xiying areas and waited for orders. The battle was commanded by the Eighth Route Army headquarters and was launched on August 20. [4] According to the headquarters' order, the above three groups focused on reconnaissance and investigation of the enemy situation, terrain, fortifications and residents along the northern section of the Zhengda Road and Tongpu Road. On this basis, they determined the combat deployment of their groups, secretly mobilized troops, organized the participating troops to conduct short-term attack and road-breaking training, prepared supplies and equipment, and carried out pre-war mobilization. The local government vigorously organized and mobilized the masses and prepared various support work.

On July 27, the Jin-Cha-Ji Military Region issued a combat order, made preliminary deployments, and ordered the deputy chief of staff of the military region, Tang Yanjie, to lead reconnaissance personnel to conduct reconnaissance near the Zhengtai Railway. On the afternoon of August 15, the military region held a combat meeting for the main offensive (the eastern section of the Zhengtai Railway) in Diaoer Village, and decided to deploy 8 infantry regiments, 1 cavalry regiment and two cavalry battalions, 3 artillery companies, 1 engineering company and 5 guerrilla detachments to form 3 main columns (namely the right column, the central column and the left column), 1 clamping force and the general reserve force to undertake the Zhengtai Railway combat mission. At the same time, the deployment of the Pinghan Railway Gaobeidian to Shijiazhuang (excluding) section, the Beining Railway Pingjin section, and the Jinpu Railway Botou Town to Tangguantun section was also made, requiring that the above-mentioned Japanese military transportation lines must be cut off to ensure the smooth progress of the main offensive. In addition, the 2nd, 5th and 8th Military Sub-districts were deployed to carry out clamping activities in the northern section of the Tongpu Railway, the Yanbei area and along the Jinpu Railway. [4]