How did Genghis Khan breach China Great Wall?

Genghis Khan (1162 - 1227), the founder of the Mongol Empire, was the only one who breached the Great Wall of China in its 2,700-year-history. In his lifetime, Genghis Khan led his Mongolian army to break through the Great Wall not only once, but several times at Wusha Fortress, Juyongguan, Zijingguan, and Tongguan, etc. These successes were a big help in overthrowing of the Jin Dynasty (1115 - 1234 AD) and founding of the Yuan Dynasty (1271 - 1368 AD).
 

In 1211, Genghis Khan ordered his army to attack the Wusha Fortress, located between Fengning County of Hebei Province and Shangdu County of Inner Mongolia. However, the Jin Court had renovated the fortress beforehand and built a secret passage to connect the fortress with the Wuyue Camp. When the battle started, Jin soldiers came streaming through the passage. Later, the Mongol army found the secret, cut the passage and easily captured the fortress.
 

Also in 1211, after Genghis Khan captured Huailai in Hebei and Yanqing in Beijing, he chased the Jin army all the way to the Juyongguan Great Wall. Seeing the solid pass, Khan gave up the idea of attacking directly, but decided to lure the Jin soldiers out for a field battle. After several small-scale strikes, the Mongol soldiers threw down their weapons, left their horses and “escaped”. As expected, the Jin soldiers on guard left the pass to chase them. Suddenly, numerous Mongol soldiers appeared from nearby mountains and surrounded the Jin soldiers, defeated them and captured Juyongguan Pass.

After breaching the Juyongguan Great Wall, the Mongol soldiers ransacked the pass and residents and left fully loaded. In 1213, in need of entering the Central Plain, the Mongol army took Juyongguan once again. After the previous failure, the Jin army had sealed the north gate with melted iron and set a large area of iron caltrops in front. This time, Genghis Khan led his army southward via a side road to Zijingguan, took that weaker guarded pass first, and then attacked Juyongguan from its south gate. The Juyongguan was recaptured.
 

This one happened in 1216. Genghis Khan ordered his general Samuhe to threaten the then capital of Jin court, Kaifeng in Henan from the west. Reaching Tongguan Pass of the Great Wall in neighboring Shaanxi for the first time, Samuhe avoided it due to its impenetrability. Coming to the pass a second time, he again did not attack it directly, but captured its southern barrier, Jinkeng, first and planned to attack Tongguan from the south. The backup army of Jin did not arrive in time and Tongguan was breached under the severe attack of the Mongol army.

In addition, the Mongol army captured many other fortresses along the Great Wall, including Gubeikou and Datong. The Mongol army kept going in and out of the Central Plain via the Great Wall freely frequently during the later battles, untill they finally overthrew the Jin Court.
 

Genghis Khan spent five years making thorough preparations for his battle against the Jin court:
1. He defeated the Western Xia to its west, which was an “assistant” to Jin but a threat to the Mongols;
2. He defeated the enemies to his north to ensure the safety of his territory;
3. He recruited the Jin army which guarded the northwest section of the Jin Great Wall, making the area a military base for attacking Jin;
4. He subverted the Jin garrison soldiers for his use;
5. He collected information on the Jin court from businessmen and envoys.

On the other side, the Jin emperor did not take the Mongols seriously at first and put most of his military forces on the southern border with Southern Song (1127 - 1279 AD). Also, having fallen into disrepair in many parts, the Great Wall at that time was not as solid as it used to be. 

 Note: The place names mentioned in this article are all current names.

Further Reading on Famous Great Wall Battles:

 General Meng Tian Attacked the Huns in the North

 Wei Qing and Huo Qubing Beat Back the Huns

 Tumu Crisis

 The War of Shanhaiguan Great Wall

 Battle of Rehe - Last Battle on the Great Wall 

 See also: Top 8 Great Wall of China Events in History