Chai Shao received the news and met him at the city gate.
"Officer Fang, we're counting on you this time!"
He truly had no other ideas.
Goguryeo also had cannons for field battles, and they possessed a substantial amount of gunpowder and shells.
His own side was at a numerical disadvantage.
If a real battle ensued, it was possible that their remaining twelve cannons would be captured by the enemy.
Ever since he saw the urgent message sent from Chang'an via six hundred li express.
He had been longing for Fang Er's arrival, and finally, he had.
Although he didn't know what method Fang Er would employ.
It was far better than having no clue.
"It's alright, don't worry too much. Since I've arrived, I certainly won't let Goguryeo have its way."
Fang Er spoke to reassure him.
This matter was not insignificant.
If they could retrieve or destroy the cannons, there would be no trouble.
Conversely, the trouble would be immense.
And he, Chai Shao, would definitely be held accountable.
"Brother Fang!"
Cheng Chumou and Yuchi Baolin were also very happy to see Fang Er.
"Brother Fang! Come, let us host a welcoming feast for you."
Cheng Yaojin, with one hand on each of their shoulders, pulled his son and Yuchi Baolin behind him, patting Fang Er's shoulder as he spoke.
Chai Shao and Zhang Gongjin rolled their eyes.
"Damn it!"
This seniority, it truly made no sense.
Weren't they going to be mindful of appearances?
Upon entering Beiping City, Fang Er looked around.
The city was not large, spanning no more than two li in each direction.
It was no wonder the Goguryeo forces weren't attacking the city.
With a small city, the advantage of a large population couldn't be utilized.
Moreover, cannons were already mounted on the city walls, three on each side.
If they were to storm the city like ants, an unknown number of soldiers' lives would be lost.
The original officials in the city had been eliminated by Luo Yi.
The official yamen had been repurposed by Chai Shao as the command post.
"Tell me, what's the current situation?"
At the banquet, after the initial pleasantries, Fang Er asked.
"That scoundrel Luo Yi has completely colluded with Goguryeo. Previously, they joined forces to attack Beiping Commandery, but were repelled by our firepower. He now occupies Liucheng Commandery, ceding Yanjun and Liaodong Commandery to Goguryeo in exchange for their troops and provisions."
Fang Er had a rough idea of Liaodong Commandery's location, but he was unsure about Liucheng Commandery and Yanjun.
He requested a map from Chai Shao and spread it out, carefully comparing it with his memory of later maps.
"I must say, the maps of this era are utterly ridiculous! There's nothing on them!"
He could only see the approximate locations.
Yanjun was the area around Huludao and Jinzhou, while Liucheng Commandery was located near Jianchang.
It wasn't too precise, but it was the general region.
"This is a classic pincer formation. With only the remaining six to seven thousand men of Chai Shao, daring to leave the city would be suicidal! And the Tang troops originally stationed here were all lured away by Luo Yi! So Chai Shao is in a dilemma! Advance, and he perishes! Retreat, and he loses the city!"
Fang Er was also somewhat troubled.
He vaguely recalled from his past readings that after Luo Yi rebelled, he defected to Jieli, and was killed by his subordinates en route.
But damn it, this script was all wrong! Why was he given this kind of script!
Was it that Yuchi had scared Jieli?
Or had it directly driven Luo Yi to despair?
Trading two commanderies for Goguryeo's protection?
How many troops did Goguryeo send? Where were the cannons? Had it been investigated clearly?
Fang Er scratched his head.
"There's no point in talking now. Let's first disable Goguryeo's cannons."
"All eight cannons are in Yanjun!"
Zhang Gongjin pointed to the location of Yanjun on the map.
"We can't attack the city. They have cannons, and attacking would put us at a disadvantage fighting uphill. We need to find a way to lure them out! As long as they dare to bring out their cannons, I can disable them!"
Fang Er said with great confidence.
"Then, how about I lead the troops to lure them into attacking?" Cheng Yaojin offered from the side.
"No, a feigned attack won't deceive Goguryeo!" Chai Shao retorted.
"Then what should we do?" Cheng Yaojin spread his hands.
"If not a feigned attack, then we'll feign a retreat!" Zhang Gongjin seemed to have an idea.
"We'll pretend to be short on provisions and retreat. Surely Goguryeo wouldn't just let such a city go? After they send out their troops, we can quietly turn back halfway and ambush them! Just like when Da Lao Hei and Baolin ambushed Jieli!"
He spoke while gesturing on the map.
Fang Er's gaze followed his fingers across the map.
Suddenly, he noticed a place.
"General Zhang's idea is excellent. I believe there should be Goguryeo spies in the city. Let's do as General Zhang suggests and feign a retreat. You lead the main army to retreat towards Zhuo Commandery, while I lead the men who came with me to ambush here. When the Goguryeo army passes, we will strike them head-on!"
Fang Er said, forcefully tapping a spot on the map.
There.
It was the location of Shanhaiguan.
Although it was an unknown small fishing village at the time, and not yet the "First Pass Under Heaven" of the Great Wall.
However, the essential pass between the mountains and the sea was an excellent place for an ambush!
Chai Shao looked at the spot he pointed to.
His eyes also lit up.
"It's feasible!"
And so, the plan was settled.
They spent a day finalizing the details.
Chai Shao would lead the main army to retreat towards Zhuo Commandery.
Fang Er would lead his musketeers and the Expel Barbarians Army to retreat with the main army, feigning to fall behind halfway and return to ambush at Shanhaiguan!
That night.
The location where the Tang army stored its provisions caught fire for no reason.
The city was thrown into chaos.
After some effort to extinguish the flames, it was discovered that the provisions had been completely burned.
Chai Shao publicly announced the retreat.
Including Fang Er's men, a total of over seven thousand soldiers retreated in disarray towards Zhuo Commandery.
Fang Er's guess was correct.
There were indeed spies from Goguryeo and Luo Yi in the city.
The spies from both sides followed the Tang army from a distance, feeling uneasy.
After personally witnessing the Tang army pass by Yuyang Commandery without any intention of entering, and instead heading straight towards Zhuo Commandery.
They then turned back, rushing separately towards Yanjun and Liuhe Commandery.
Two days later.
Luo Yi and the Goguryeo general Yeon Gaesomun simultaneously received the news sent by the spies.
Luo Yi was already intimidated by the cannons and remained obedient, not attempting any minor maneuvers.
In Yanjun.
Yeon Gaesomun looked at the generals under his command.
"The Tang army has retreated, leaving an empty city. Who will go and take it for me?"
"Great General, the city is easy to take, but it needs cannons to defend it. Otherwise, by the time that Tang army returns with sufficient provisions, without cannons, I fear we won't be able to hold it. If you give me half the cannons, I can surely capture Beiping Commandery for you."
A man with a saber at his waist declared loudly.
"Impossible! The cannons cannot be moved lightly! I have already ordered people to return home to gather craftsmen. Until we learn how to replicate them, no one is to touch these eight cannons!"
Yeon Gaesomun adamantly rejected the man's suggestion.