The Forbidden City in central Beijing was constructed between 1406 and 1420 during the reign of Emperor Yongle. Spanning approximately 720,000 square meters and comprising nearly 1,000 buildings, it served as the residence and administrative center for Chinese emperors for over 500 years.

Given Beijing's continental climate, characterized by hot, humid summers and deep, cold winters, preserving food, medicinal herbs, and maintaining a stable environment for the large-scale wooden structures posed a challenge for the imperial court. To address this, the imperial family constructed a system of ice cellars, known as "bing jiao", located beneath the palace grounds.

An ice cellar repurposed as a cafe. Photo: N509FZ

According to documents from The Palace Museum, the ice cellar system was widely used during the Qing dynasty and underwent several renovations during the Qianlong era.

The cellars were semi-subterranean to leverage the stable underground temperatures and minimize ice melt. Their thick walls, constructed from multiple layers of fired bricks, combined with vaulted roofs, supported the earth covering above. Inside, a drainage system channeled melted ice water out, reducing humidity and maintaining low temperatures within the storage space.

Each winter, when Beijing's lakes and moats froze, the imperial court organized ice harvesting for storage until the following summer. Large blocks of ice were cut, stacked in the cellars, and separated by straw or sawdust to reduce heat exchange.

Entrance to the ice cellar area at the Forbidden City. Photo: N509FZ

According to some historical records from the Qing dynasty, the imperial family stored tens of thousands of ice blocks annually for daily use within the palace. In addition to the ice cellars, the court also utilized "bing jian", containers made of precious wood or metal, which held ice to cool indoor spaces. Cold air diffused through openings on the lid and sides of the boxes, lowering room temperatures. Bing jian were also used to preserve fruits, food, and medicinal herbs during summer.

Today, the ice cellars in the Forbidden City are no longer used for ice storage. The ice cellar area is located on the west side of the Forbidden City, near Cining Palace. Following renovation and preservation efforts, many areas have been opened to visitors, while some have been converted into restaurants and cafes for visitors to relax within the Forbidden City grounds.

Visitors can now observe the thick brick wall structure, vaulted roofs, and characteristic semi-subterranean design of the complex. This space offers a glimpse into how ancient people adapted to climate conditions before the advent of modern refrigeration technologies.

Mai Phuong (According to Sohu, Visit Beijing)