When Qiao Youhua sent a telegram to Guo Meng and asked them to transport the poison gas bombs, it was in the morning, and after more than ten hours of emergency transportation, the transport troops sent by Guo Meng quietly transported hundreds of poison gas bombs to the camp of the dragon's tooth column outside Niangzi Pass at nine o'clock in the morning and evening.

At this time, the sky was already dark, Qiao Youhua, Zheng Yunshan, Zhao Youde, and the officers and soldiers participating in the battle had all eaten dinner, and they were all resting except for the necessary vigilance troops.

Knowing the arrival of the poison gas bomb, Qiao Youhua immediately came to the spirit, summoned Zheng Yunshan, Zhao Youde and others and ordered: "The poison gas bomb has arrived, I have decided to launch a surprise attack on Niangzi Pass on time at twelve o'clock, and the guard regiment will still serve as the main attack, and the other troops will be in reserve, ready to support at any time." ”

Zhao Youde and the others nodded one after another, after all, gas masks are standard equipment for all officers and soldiers of the guard regiment, but other troops such as the Third Division do not have them.

Political Commissar Guo Meng mainly brought poison gas bombs this time, but there was no gas mask, so it was only fitting that the guard regiment would be the main attacker.

After Qiao Youhua gave the order, thousands of officers and soldiers participating in the battle quickly began to act quietly, especially the officers and men of the guard regiment who served as the main attack, and the artillerymen who were responsible for the artillery attack.

In the dark of night, the artillerymen, with the assistance of the 3rd Division and other infantry officers, were quietly unloading boxes of poison gas bombs from military trucks and carrying them to the vicinity of each artillery gun on their artillery positions to prepare for the shelling.

In order to ensure the success of this assault battle, Zheng Yunshan's guard regiment decided to have 500 people as the first batch to participate in the assault battle later in the assault.

Therefore, the nearly 3,000 soldiers of the guard regiment were divided into two parts, and the first batch of 500 people, fully armed, quietly moved to a place less than 400 meters away from the Niangziguan city wall in the night, and quietly hid with the help of the special terrain cover at the bend.

The remaining 2,000 people followed, standing by in a wider area beyond the kilometer of the city walls.

The five hundred commandos were personally led by Zheng Yunshan, and in the dark night, Zheng Yunshan took out a gas mask and said in a low voice: "Put them all on, and you will listen to my orders later!" ”

After saying that, he took the lead in putting on a gas mask. The other fighters silently took out the gas masks they were carrying and put them on.

In the suffocating wait, time passed by minute by minute, and by about ten o'clock in the evening, the artillery and infantry were ready.

At eleven forty o'clock, Qiao Youhua, who was standing in the command post, raised his hand and looked at his watch, and immediately ordered Li Yansan behind him: "The time is almost up, order the artillery to open fire immediately, first ten rounds of poison gas shells, and then replace them with regular shells, ten rounds of rapid fire."

Finally, they were replaced with poison gas bombs, and after the three rounds of mixed shelling, the commandos of the Guards Regiment were ready to attack. ”

This method of mixing the use of artillery shells was carefully considered by Qiao Youhua to ensure the double killing of poison gas shells and conventional artillery shells, and to maximize the power of artillery attacks and kill and injure the Japanese puppet army.

Li Yansan suddenly stepped forward and answered yes, and hurriedly received the order.

Soon, after receiving the order, on the artillery position, which had been waiting for the battle but had been silent until now, there was a muffled sound of cannon ejection, and under the dark night, clouds of smoke from the poisonous gas ejection chamber flew away, and diffused from the tail of the gun and the muzzle.

In the muffled sound of tom tom, a poison gas bomb rose into the air one after another, piercing the dark night sky, and smashed towards the head of the Niangzi Guandongmen Castle.