"This country clearly bears the mark of the Jurchens. Perhaps that's fortunate—it has made it easier to continue my reforms. Even the Eight Banners I created were originally modeled after military forces that became the foundation of the Qing. First, I must somehow take control of the Three Hans. Once that is done, I will be the true master of the Three Hans—and the Jurchens will be fully incorporated into them. Later, I can even fabricate a text claiming the Jurchens and the Three Hans share the same bloodline."
Though Tang had recognized Da In-seon as the King of Goryeo, the influence of the Jurchens remained strong. From the days of Balhae, before the kingdom's name changed, a culture fused of Goguryeo and Malgal had persisted. This could not easily be undone. To stand proudly as Goguryeo's legitimate successor, the culture, people, and bloodline of the Three Hans had to be fully unified.
Having claimed Goryeo with authority over the Khitans, Gung Ye, and Wang Geon, Da In-seon still felt uneasy.
He repeatedly warned himself: this was merely a matter of cultural fusion, separate from legitimacy.
There was no room for melancholy. To unify the Three Hans, Baekje had to be struck decisively.
"Establishing a modern military system now would be impossible. Even just setting up the firearms corps is enough to exhaust the troops."
The army would not accept such a system yet.
The Jurchens had not fully integrated into settled life. They were being gradually absorbed into Goguryeo through Da In-seon's assimilation policies, while a strong cavalry system needed to be maintained. Though difficult, it was necessary. Attempting modern reforms now might provoke resistance.
With the aqueduct completed, rice transplanting methods spreading among the people, and the firearms corps in progress, there was no urgent need to rush.
The Cold War with Baekje and Daeya Fortress did not end until spring of 899.
Now, Later Baekje began full-scale attacks. King Geon-hun personally led forces with generals Park Yeong-gyu and Chu Heo-jo to subjugate Silla.
Interestingly, many of the figures historically appearing in the 900s for Later Baekje were showing up now.
Currently, the Baekje army stationed Kim Hwon, Ae-sik, Han Jang, and others on the frontlines against Goryeo.
'Why are these figures appearing now? This is ridiculous. Is this really another world?'
In response to Baekje's provocations, Balhae's civil and military officials, along with Da In-seon's advisors, convened a strategy meeting.
The consensus: Baekje must be punished.
By then, the aqueduct was complete, and the firearms corps was operational. Han troops eager to become professional soldiers had been organized into the Han Eight Banners, while Khitans integrated into Goryeo and Uighurs who had defected from the Mongolian steppes formed the Mongol Eight Banners.
Originally, the Uighurs had, until 840, built an empire that extorted Tang and subordinated the Khitans. Eventually, their empire declined, crushed by the Kyrgyz, and the people scattered into small groups. Recently, these dispersed Uighurs had begun naturalizing into Goryeo, and Da In-seon incorporated them along with the Khitans into his military.
"Baekje will crumble like leaves in the wind with just the firearms corps. Even Yu Geum-pil can't handle them," he said.
"But Your Majesty, we must not underestimate them. Should Baekje concentrate its forces, we risk being pushed back to Songak unless we mobilize a large army."
Baekje controlled parts of Chungcheong and Jeolla provinces, with high agricultural output and a population exceeding Silla's. While smaller than Goryeo, historically, they could muster armies of 100,000—a force capable of significantly affecting Silla or Goryeo.
"Quite a few generals have appeared. Silla's pirates have all been subdued,"
"Yes. The Baekje forces now stationed along our border may be retaliating for those pirates."
Previously, Da In-seon had instructed Silla's pirates to raid Baekje without involving Goryeo's navy. Baekje had annihilated the pirates, leaving Geon-hun unconcerned.
Having reaped sufficient benefits, and with the pirate operations consuming time, Da In-seon was satisfied.
"So what of Silla?"
"Excluding Daeya Fortress, Baekje continues to provoke them. It's quite a strain."
"Since we've already taken so much from Silla, it must sting their pride to be beaten by Baekje. Send the Han and Mongol Eight Banners to reinforce them."
While aiding Silla was partly a matter of Da In-seon's pride, allowing Baekje to overrun Silla would also harm Goryeo. He promptly dispatched the banner troops.
With construction complete and resources ample, the time had come to gradually crush the Later Baekje forces.
Now, Da In-seon commanded the firearms corps—the era's most advanced army, capable of powerful combat with a pseudo-tercio formation, among Goryeo's elite units.
"We will also test the firearms corps this campaign. Until Baekje is destroyed, Gaegyeong will serve as the temporary capital where I will remain."
"Your Majesty, that is unwise! Our army has many renowned generals; must you lead personally?"
During previous uprisings, many respected generals had emerged from the Eight Banners, alongside Yu Geum-pil and Park Sul-hee. There was no need to involve Wang Geon, nor did Da In-seon need to personally join the frontlines. Historically, kings often led troops, but reality differed. His frequent presence on the battlefield unsettled Goryeo's officials, as he had no heir yet.
"But Geon-hun is personally involved. Shouldn't we also attend formally?"
"Indeed, Your Majesty!"
Even the Goryeo bureaucrats could not easily resist.
Goryeo had become the leading kingdom of the Three Hans, surpassing even Goguryeo's glory. The young king had expanded Goryeo's territory and earned recognition from Tang. There was no reason for Da In-seon to risk personal danger unnecessarily.
"Very well. I will go personally. Inform the Silla queen that we shall meet in Gaegyeong regarding Baekje."
'Queen Jinseong's slightly longer reign than in history makes this convenient. If King Hyogong were on the throne, it would have been much worse. At least Jinseong is easy to handle.'
"Your Majesty!"
With absolute royal authority, Da In-seon ignored his ministers. Even his closest advisors, Dae Wi-hae, O So-do, and Choi Seung-woo, had half-surrendered to the inevitability of his personal leadership. There was no reason for officials to oppose him.
Moreover, Da In-seon possessed a secret advantage.
"I know your concerns. Even if I return safely, a ruler absent too often invites instability. Hence, Gaegyeong will serve as the temporary capital. Do not interfere further. You will govern the people there, ensuring my campaign is fully supported. Chief Minister, Right and Left Ministers, attend to this. Maintain legitimacy and coordinate all departments to back my war effort."
"Yes, Your Majesty. Understood."
Although they responded, the ministers could do nothing to prevent his departure, and unease was evident on their faces.
Each feared for his life, wondering if Da In-seon might fall in battle. They felt inadequate whenever he led the army personally.
"All we can do is support His Majesty faithfully from behind."
"Exactly. Our duty is to back him so that he may fight successfully."
Once Da In-seon's orders were issued, the department corresponding to Tang's Ministry of War mobilized for battle. Gaegyeong became the temporary capital, and the Eight Banners, firearms corps, and supporting forces from Namhaebu and Pyongyang were assembled for the Baekje campaign.
Before the campaign, there was a minor quarrel with Queen Sul-yul-pyeong.
"I shall go with you this time as well."
"Queen, where do you intend to go in that condition?"
He was incredulous. Though not pregnant, her belly already held a child. How could she accompany him to the battlefield? Yet even Da In-seon could not easily refuse his wife.
"My efforts to advance Goryeo's culture have kept me busy. You must grant me this small request."
"…Remain in Gaegyeong. That is non-negotiable."
"I will comply."
Unable to resist her, Da In-seon accompanied Queen Sul-yul-pyeong to Gaegyeong with the Baekje campaign forces in the autumn of Year 5 of Yeongrak.
Upon receiving Da In-seon's letter requesting discussions on upcoming matters, Silla dispatched Queen Jinseong and Choi Chi-won to Gaegyeong. By now, Silla was effectively a Goryeo protectorate, with most soldiers stationed by Goryeo, so the queen's absence posed no real problem.
Upon arrival, Da In-seon informed Yang Gil of the firearms corps' presence, established a training ground, and positioned reinforcements from Pyongyang and Namhaebu along the Baekje border.
'We must conclude the war within a year, keep Japan subdued, and begin full-scale gunpowder production.'
Now, 30,000 troops were stationed along the Baekje border, and a combined 50,000, including the Eight Banners and firearms corps, garrisoned Gaegyeong. With the additional troops in Silla, the total force approached 100,000. Da In-seon had come prepared.
"Your Majesty, the Silla queen has arrived in Gaegyeong."
"Good. I will meet her shortly."
As Gaegyeong was prepared as a temporary capital, Da In-seon, Queen Sul-yul-pyeong, and the court officials welcomed the Silla queen.
In Da In-seon's eyes, Queen Jinseong was tall and well-built, able to dominate most men of the era, and exceptionally beautiful for her age.
The queen, too, was impressed by Da In-seon.
A much younger man had expanded Goryeo's territory, strengthened its power, and been fully recognized by Tang as its king. That he was only twenty astonished both the queen and Silla's officials.
"I had no idea the king was so young," she admitted.
"Ha ha! And you are a young queen yourself."
'To think he accomplished so much at this age. Balhae developed under him so impressively.'
Choi Chi-won, entering Gaegyeong, witnessed the firearms corps' training firsthand and was astounded.
Of course, this was by Da In-seon's design: the training grounds were deliberately set along the route for the Silla queen and her officials.
Seeing troops armed with thunderous firearms, lined in formation and striking targets with explosive volleys, the Silla delegation was shocked. If even the Gaegyeong residents were impressed, the reaction of the Silla officials was nothing short of astonishment.
After the display, Da In-seon hosted a conference with the Silla queen at the temporary palace in Gaegyeong.