The officers and men of the 93rd Division on the battlefield also clearly heard the roar of engines in the sky when the Japanese planes approached. Without such specialized anti-aircraft weapons as anti-aircraft guns, light and heavy machine guns in the troops became quasi-weapons that could be used for air warfare.

The most effective anti-aircraft machine guns are equipped with heavy armored vehicles and light tanks, followed by the small number of Type 6 or 7 heavy machine guns in the troops. The Type 67 heavy machine gun was replaced with an anti-aircraft tripod and could be used for anti-aircraft firing missions. After the infantry had properly dispersed and concealed, the focus of air defense became the positions of the heavy artillery regiment that were shelling Lang Son Thanh and the iron bridge over the Qu Chi River.

Sure enough, as soon as the Japanese planes arrived at the battlefield, more than a dozen bombers swooped down in groups of several and successively towards the artillery positions. More than 20 combat vehicles that had just arrived next to the artillery position set up a fire net with vehicle-mounted antiaircraft machine guns, and the first round of dive bombing by the Japanese bombers was not too successful; four planes were hit by bullets and caught fire and fell, and more than a dozen bombs and bombs fell on the artillery positions, and the rest of the bombs and bombs fell outside the positions.

The Japanese dispatched a bomber squadron and an escort fighter squadron this time, and the bombers of the squadron were three squadrons with a total of 36 aircraft. The first round of dive bombing was carried out by a bomber squadron, and the Japanese did not expect that so many anti-aircraft weapons would exist. The plane's bombing targets then turned into vehicles with anti-aircraft machine guns and heavy machine gun fire points from the ground to the air.

As soon as the Japanese planes changed their targets, the tanks were somewhat unable to cope with them, because the tanks were not specialized anti-aircraft weapons and did not have the flexibility of airplanes. Seeing the planes swooping down towards them, the chariots scattered one after another, firing into the air as they moved. In this way, this round of bombing by Japanese planes also injured two light tanks and four heavy armored vehicles, and one light tank and one heavy armored vehicle were unfortunately directly hit by * and burst into fire and explosion on the spot.

The Japanese bombers took turns to dive and bomb, and after throwing out the bombs and bombs, they also used their airborne machine guns with their fighters to strafe the officers and men of the 93rd Division. More than half an hour later, the Japanese army began to return home, and the positions on the north bank of the Qiqi River were full of craters, and gunpowder smoke rose into the sky. Li Yuanhong, Huang Gang and others, who were hiding in a bunker, looked at the mess on the battlefield and hid into deep self-blame.

Due to the bombing of Japanese planes, the shelling of Lang Son Fortress was abandoned halfway. After the bombing by Japanese planes, the heavy artillery regiment of the 93rd Division suffered considerable losses, 10 150-caliber heavy howitzers and 12 122-caliber grenades and artillery pieces were blown up, more than 200 officers and men were killed or wounded, and the attack on Lang Son City was temporarily suspended. In addition to the losses of officers and heavy artillery regiments, the armored brigade also lost four light tanks, six heavy armored vehicles, eight light armored vehicles.

As soon as the Japanese air raid ended, Li Yuanhong sent a telegram to Wang Haitao requesting punishment, and reported the losses in the telegram. After receiving the telegram, Wang Haitao also blamed himself. In the previous battles, whether it was the battle against the 14th Army or the counterattack against the 16th Army, there was no large-scale bombing by Japanese aircraft. The losses of the 93rd Division and the Armored Brigade under the bombing of Japanese planes this time were also caused by their own negligence, and they also had to pay considerable responsibility.

Wang Haitao immediately sent a telegram to Li Yuanhong, asking the 93rd Division to suspend the attack on Langshan City and rest in place and wait for orders. While resting, it is necessary to pay attention to air defense and the protection of the iron bridge over the Qianqi River. After sending the telegram to Li Yuanhong, Wang Haitao sent another telegram to Tang Renxin in Longzhou City, asking Tang Renxin to immediately mobilize two antiaircraft artillery regiments to help in the battle.

At present, Wang Haitao's anti-aircraft firepower is not weak, not only the 50 37-mm caliber double-barreled antiaircraft guns taken from the munitions warehouse, but also the nearly 200 antiaircraft guns obtained from the Germans on several occasions, except for some of which were allocated to important departments, the rest were under the name of the heavy artillery brigade and divided into three antiaircraft artillery regiments.

Of the three anti-aircraft artillery regiments, two were equipped with anti-aircraft guns on armored trucks, and only one was an original German self-propelled anti-aircraft gun. After receiving Wang Haitao's telegram, Tang Renxin did not hesitate to send the two strongest antiaircraft artillery regiments in battle, one was a German-made self-propelled antiaircraft artillery regiment, and the other was a 37-millimeter double-barreled antiaircraft artillery regiment modified on armored trucks.

The mobility of these two anti-aircraft artillery regiments was very strong, and Tang Renxin filled 30 armored personnel carriers of the armored brigade with a battalion of fighters to escort the antiaircraft artillery regiment into action. In three days, this reinforcement rushed to Zhennanguan. Wang Haitao was also relieved to see the arrival of two anti-aircraft artillery regiments and 100 anti-aircraft guns.

During these three days, although the 93rd Division did not launch an attack on Lang Son City, Japanese planes still came to bomb twice a day. The goal of both sides was the iron bridge over the Qiqi River, and the Japanese planes had a clear purpose, that is, to blow up the iron bridge, while the 93rd Division had to defend the iron bridge. The Japanese troops in Lang Son City once sent an infantry squadron to capture the iron bridge when they were bombed by planes, but naturally they broke their heads and bled back.

During the three-day confrontation, the 93rd Division and the armored brigade shot down 12 Japanese planes, and they also paid the price of 10 combat vehicles and more than 100 officers and men. As soon as the two anti-aircraft artillery regiments arrived at Zhennan Pass, Wang Haitao immediately ordered them to rush to Langshan City overnight to join the 93rd Division. And let the two regiment commanders, Yang Yang and Luo Hong, obey the command of Li Yuanhong, the commander of the 93rd Division.

The arrival of the two anti-aircraft artillery regiments made Li Yuanhong feel very reassured, Li Yuanhong knew that his ability to use anti-aircraft guns was limited, so he did not mention anything about commanding these two anti-aircraft artillery regiments, but only told Yang Yang and Luo Hong, the two regiment commanders, that the Japanese bombing and the target he must hold were the iron bridge on the Qiqi River, and as for how to arrange the anti-aircraft guns to attack the Japanese aircraft most effectively, he left it to the two regiment commanders to arrange by themselves.

Yang Yang and Luo Hong took advantage of the night to inspect the position for a long time, and after some discussion, they came up with a layout plan. The two regiments and four reinforced battalions were divided into four parts, of which two battalions of the double-barreled anti-aircraft artillery regiment set up two fire interception nets north of the iron bridge, with 25 guns per battalion as one. These two firepower interception nets were used to prevent Japanese planes from diving and bombing.

In addition, the two battalions of the self-propelled antiaircraft artillery regiment were in front of and behind the two firepower interception nets, and the auxiliary ribs were the two firepower interception nets to deal with the Japanese planes. After planning the position, the two anti-aircraft artillery regiments took advantage of the dawn to enter the designated positions and began to camouflage themselves. By daylight, the two anti-aircraft artillery regiments had completed their preparations and were waiting for the arrival of Japanese planes.

At 8 o'clock in the morning, 60 medium bombers from two Japanese bomber squadrons arrived over the battlefield under the cover of 12 fighters from a fighter group. With the experience of the previous days, the pilot plane swooped directly towards the iron bridge. In the previous days of bombing, the Japanese planes had already known that the Chinese army would use machine guns to form a fire network to stop their own bombing, but the power of the machine guns was limited, and as long as they were careful, they could be evaded.

Even if you can't dodge, as long as you don't hit the vital parts, the plane won't be destroyed, and you can fly back. Therefore, after reaching the right position, the first group of Japanese planes did not hesitate to dive and pounce on the iron bridge. In the second day of bombing, this iron bridge has already suffered a lot of bombs and bombs, and if it were not for the solid and all-iron structure, this iron bridge would have been blown up long ago, and this iron bridge would no longer be able to withstand a few bombs and bombs.

As soon as the Japanese planes dived, the first interception fire, which had been waiting for a long time, opened fire. The sudden appearance of anti-aircraft artillery interception nets was no match for machine-gun firepower, which also made the unprepared Japanese planes suffer a big loss. In a few tens of seconds, five of the eight bombers in the first batch of dives were hit, three exploded into flames in the air, and the other two were also hit by bullets and caught fire, and fell headlong into the ground.

The three Japanese planes that were lucky enough to rush through the first interception fire network were about to drop bombs in a panic and left, when the second interceptor fire network opened fire. This time, the three planes did not escape the fate of being hit, and at the same time they were hit by bullets and caught fire and planted to the ground. All eight planes were shot down in a single dive attack, which caused chaos among the Japanese planes that had not dived down closely.

The planes that were preparing to dive down the second batch hurriedly pulled up, and dozens of Japanese planes spun around the sky a few times before they reorganized their formation, and with fierce momentum, they directly pounced on the antiaircraft artillery interception position. Looking at the Japanese planes that were rushing towards him, the double-barreled antiaircraft guns on the second interception fire net opened full firepower, and the shells directly met the Japanese planes.

At this time, the two self-propelled anti-aircraft artillery battalions that were helping the side also moved to a suitable position and launched an attack on the Japanese planes. This ground-air battle was fought extremely fiercely, which made Li Yuanhong, Huang Gang, Wu Jianzhou and others who were hiding in the bunker watching the battle thrilling. Whenever a plane was hit by a bullet and caught fire, or exploded in the air, or fell headlong, Li Yuanhong and his family would cheer.

The battle lasted for more than an hour, and the Japanese planes finally flew away, and in this ground-air battle, the two antiaircraft artillery regiments worked together to destroy and shoot down a total of 46 Japanese planes, and they also lost more than 20 antiaircraft guns and suffered more than 120 casualties. Yang Yang and Luo Hong, the two regiment leaders, had a smile on their faces, compared to the loss of the Japanese machine, their own loss was nothing.

The Japanese planes suffered a big loss, which greatly annoyed the navy, and for two days in a row, a large number of planes were sent to retaliate. But under the counterattack of the anti-aircraft guns of the two regiments and the ground machine guns, they all suffered losses. Two days later, the navy could no longer bear the loss of aircraft and rejected the request of the Southern Army Command to send aircraft to the Vietnamese side.