Among the many legends of the Great Wall, none is more beloved than the story of the “Ratifying Brick” (Dingcheng Zhuan) at Jiayuguan.

The Impossible Calculation

In the 1530s, the Ming court commissioned the construction of Jiayuguan’s imposing gate tower. Master craftsman Yi Kaizhan was tasked with the project. Known for his extraordinary mathematical abilities, Yi calculated the exact number of bricks needed: 99,999.

The supervising official, suspicious of such precision, threatened Yi: “If you are off by even one brick, you and your workers will be executed.”

The Extra Brick

When construction was complete, the official arrived to inspect the tower. To his surprise, he found not 99,999 bricks — but 100,000. One extra brick sat on the gatehouse floor.

Triumphant, the official prepared to execute Yi Kaizhan. But the craftsman remained calm. “That brick,” he declared, “was placed by the gods to stabilize the wall. Remove it, and the tower will collapse.”

The official, unwilling to risk divine wrath, left the brick in place. It remains there to this day — a single brick on the west gate of Jiayuguan, a monument to one craftsman’s audacity.

The Old Dragon Head (Laolongtou) at Shanhaiguan is where the Great Wall makes its dramatic plunge into the Bohai Sea. The name comes from a Ming Dynasty legend: the wall, stretching thousands of kilometers from west to east, resembled an enormous dragon — and at its eastern terminus, the dragon lowered its head to drink from the sea.

The Engineering Challenge

Building a wall into the sea presented unique challenges. The Ming engineers constructed a stone foundation that could withstand the constant pounding of waves and the corrosive effects of saltwater. The original structure, completed in 1579, used massive stone blocks fitted together without mortar, relying on their weight and interlocking design for stability.

The Chenghai Tower

At the very tip of the Old Dragon Head stood the Chenghai Tower (“Sea-Calming Tower”), a two-story pavilion where Ming generals scanned the horizon for invading fleets. The poet Sun Chengze wrote: “The Great Wall ends where the sea begins, and the waves crash against the dragon’s jaw.”

Destruction and Restoration

The original Old Dragon Head was destroyed in 1900 by Eight-Nation Alliance forces during the Boxer Rebellion. For nearly a century, only rubble remained. In 1985, a major restoration project rebuilt the wall and tower using historical records and archaeological evidence, returning the dragon to the sea.