History, too, has figures who can be called ’epic’ or the ‘GOAT (Greatest Of All Time)’. If one had to pick just one person from all of Chinese history, many would think of Emperor Taizong of Tang, Li Shimin. He was an emperor who seemed to have maxed out every skill in military, politics, and diplomacy. 🎮
He embarks on the greatest ‘raid’ of his life. The target: the persistent northern kingdom, Goguryeo. But what happened? Instead of conquering the final boss, he was ignominiously repulsed without even overcoming a small fortress, let alone a mid-boss. Today, through the hidden details in historical records, we will delve into the thrilling story of why the mighty Emperor Taizong of Tang was destined to fail in his Goguryeo campaign.
1. The Grandest of Pretexts, With an Iron Grasp
In 645, Emperor Taizong declared at the send-off ceremony, “The reason I personally lead this army is not out of desire for Goguryeo’s land or wealth. It is to save the people and to punish the traitor Yeon Gaesomun who murdered the king!” 📜 What a magnificent pretext!
When asked about Yeon Gaesomun, who had seized power through a coup, “Why did you kill the former king?”, he responded with audacious confidence, “The former king was not benevolent, so his ministers deposed him. What business is it of Your Imperial Majesty?” essentially saying, “Mind your own business regarding our internal affairs?”
Enraged, Emperor Taizong mobilized an army of hundreds of thousands, but his true motive lay elsewhere. It was Goguryeo’s source of power, its gleaming ‘iron (鐵)’.
2. The Northern Forge, A Kingdom with an Iron Heart
The Goguryeo forces that the Tang army faced were on a different level. The Gaemamusa (armored cavalry), with their entire bodies and horses clad in iron armor, were a shock to behold. Arrows shot by Tang soldiers bounced off their armor with a ’ting, ting’ sound, rendered utterly ineffective.
This was not merely a matter of bravery. Goguryeo was a colossal ‘munitions factory’ as a nation.
The Secret of Goguryeo’s Steel
Goguryeo’s steelworkers mass-produced ‘steel’, which was both hard and elastic, by mixing iron with carbon. This meant they could equip every single soldier with the highest quality weapons and armor of the era.
A Mobile Fortress Legion
Equipping 5,000 Gaemamusa required over 300 tons of iron. The industrial system itself, which mined, smelted, and processed this immense quantity of iron into armor, was Goguryeo’s true weapon. Emperor Taizong’s target was precisely this ‘iron heart’.
3. History’s Most Dramatic Siege: Ansi Fortress
In the early stages of the war, the Tang army advanced like a raging torrent. Now, only the small, dilapidated-looking Ansi Fortress stood in the emperor’s path. But no one knew that this tiny fortress would become a giant trap that would snag the feet of the great emperor.
① Drumming Towards the Emperor’s Banner
Emperor Taizong proudly erected his yellow banner, a symbol of his authority, in front of the fortress. Normally, this would lead to surrender out of fear, but the commander of Ansi Fortress is said to have led his soldiers to the ramparts and beaten drums and shouted in defiance whenever the banner was visible. 🥁 It was a formidable psychological warfare and provocation, as if to say, “The Emperor? Not scary at all.”
② The Miracle of 60 Days: The Siege of the Earthen Mound (土山)
When all attacks were repulsed, Emperor Taizong mobilized a total of 500,000 man-days to build a massive earthen mound, known as Tosan (土山), taller than the fortress walls, over 60 days. They thought victory was assured from this vantage point.
However, at that very moment, as if by a miracle, one side of the earthen mound collapsed due to heavy rain and clung to the fortress wall. A golden opportunity! Hundreds of desperate Goguryeo warriors charged through the gap and instantly captured the earthen mound. The Tang’s painstakingly constructed attack platform was instantaneously transformed into Goguryeo’s frontline stronghold.
③ The Victorious Emperor’s Silk Gift
After over two months of relentless siege, Emperor Taizong decided to retreat. However, he did not simply withdraw. He sent 100 bolts of silk to the commander of Ansi Fortress, conveying, “As you have defended your city valiantly and served me, I am pleased and present you with this silk.” It was the most peculiar and memorable gesture of respect in history, sent to the commander who had so thoroughly defeated him.
The Emperor’s Tears and Final Will
More dreadful than the defeat at Ansi Fortress was the retreat itself. It was winter, and the army suffered from freezing and starvation in the swamps of Liaodong. Emperor Li Shimin himself was reduced to carrying dirt to build roads, a truly pitiable state.
This humiliating failure left a lifelong trauma. A few years later, on his deathbed, he left the Crown Prince with this dying wish:
“Never again invade Goguryeo.”
This final confession from a conqueror who had commanded the world was not mere regret. It was a sober recognition of the reality that Goguryeo’s steel armor, its sturdy fortresses, and the indomitable will contained within them could not be broken even by the might of an empire. The roar of Ansi Fortress, echoing through a millennium, shows us that even in the face of overwhelming power, meticulous preparation and an unyielding will can create miracles.
Key References
- Samguk Sagi (History of the Three Kingdoms): Goguryeo 본기 (Annals) and related biographies. Records from the domestic side, including the exploits of the Ansi Fortress commander and Emperor Taizong’s gift.
- Old Book of Tang & New Book of Tang: Annals of Emperor Taizong of Tang and Biographies of Eastern Barbarians. Records of the war from the Tang perspective.
- Zizhi Tongjian (Comprehensive Mirror in Aid of Governance): A chronological history compiled during the Song dynasty. Details the progression of the Goguryeo-Tang War.