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…The architects would fully employ structural elements to maximize keeping in the warmth during the winter and the heat out during the summer.

During the Ming (1368–1644) and Qing (1644–1911) Dynasties, China went through the Little Ice Age. During the two cold waves in the early Qing Dynasty, even Lake Dongting and Lake Poyang in Southern China had frozen over. The capital, Beijing, counted more than 150 extraordinarily cold days each year, during which the temperature fell between 20 and 30 degrees Celsius below zero.

Keeping warm was an important daily task at the royal palace. There were special departments for winter heating in the Forbidden City, the Chinese imperial palace, which was the center to the two dynasties. During the Ming Dynasty, the Xixin Department was specifically in charge of the supply of firewood and charcoal. The fact is that Xixin officers reported directly to the Emperor, so their function was quite important at the palace.

When the first Qing Emperor took over the Forbidden City, the Xixin Department was replaced by three more specific departments: Ruohuo – installing heating ovens and transporting firewood; Chaitan – storing and distributing firewood and charcoal; and Shaokang – warming the beds. There were also people in charge of braziers in the palace.

Heating Systems

The Kang or bed stove is an effective northern Chinese means of enduring harsh winters. In the Forbidden City, it was quite a usual feature to each room. Besides being used as a bed, such activities as having meals, working or chatting on the Kang were common.

Being an officer in any one of the three departments was not an easy task. At the end of the 18th century approximately 9,000 people lived within the Forbidden City: the royal family, concubines, guards, servants, and eunuchs.

During Emperor Qianlong’s reign (1735–1796), the daily firewood and charcoal supply were as follows: 60 kg for the Empress Dowager, 55 kg for the empresses, 45 kg for the imperial concubines, 37.5 kg for the concubines, 15 kg for the princesses, 10 kg for the princes, and 5 kg for the emperor’s grandsons. This was a big task for the Chaitan department. In order to reduce smoke, high-quality firewood and charcoal had to be selected from various sources.

Traditional Chinese architecture tends to utilize the local geographical conditions and thus creates different styles. The architects would fully employ structural elements to maximize keeping the warmth in the winter and cool temperatures in the summer.

Walls in the Forbidden City were constructed as “hollow walls”. These double-cavity walls were also called “fire walls”. There were built-in tunnels within the walls. Charcoal stoves connected to the tunnels would heat the air, which would then run through the entire wall system of each unit of the palace to keep the rooms warm. Windows at the end of the tunnels allowed the smoke to escape. The tunnels’ extensions reached built-in clay beds in each room. Thus the palace was as warm as the spring. This entire ecological heating system was effective and economical—even by today’s standards.

In addition, there were many braziers in the palace, some of which could be as big as a meter high and several hundred kilograms in weight or small enough to be easily carried around. There were braziers for hands and for feet, all beautifully produced.

Colorful Winter Days

9×9 Winter Diagrams – a short poem with nine characters totaling 81 strokes. In olden times, each character stroke was filled in with a different color based on the weather of that day.

The ancient Chinese definitely were not without their own form of fun and activities. A tradition in the Qing Dynasty, known as “9×9 Winter Diagrams”, helped make even the coldest winter days a bit more cheery and colorful.

This tradition was a manner used to track the remaining days of winter through the use of vivid colors. Those in the royal palace hung a special banner marking the arrival of winter; with the objective of filling the banner with nine Chinese character, each with nine strokes. The color of the stroke was determined by the weather of that day: red for clear days, blue for overcast days, green for rainy days, yellow for windy days, and white for snowy days. Each day a person added a new stroke, ultimately leading to a Chinese character. When all 81 strokes were finally completed, winter would usually have ended and spring would have returned.

This tradition was not only displayed in the palace, but also among common folk. There were wood-carved “Plum Flowers with 81 Petals”. They could be placed on the desk and painted by brush everyday. There were other affairs involving special tablets, poetry, and couplets that also helped pass the winter days.