When there is no gas or natural gas, people cook by fire, which ranked first in ancient times, showing its importance and difficulty. With the continuous development of history, cookers are constantly changing, from the earliest kettle and tripod to cookers. Bronze furnaces in the Three Kingdoms period were well received by the public when unearthed. The shape of the whole stove is complete, and the chimney and other parts are very exquisite. The most important thing is that it is also very convenient to use. Since the Three Kingdoms period, stoves have been built faster, and stoves and chimneys have become longer and longer. All these changes are aimed at making the stove more closed, thus increasing the temperature of the stove and, more importantly, saving burning materials. Although cooking used to use a lot of fuel, most of it was wood. Although China is rich in fuel resources, with the continuous war, increasing population and expanding demand, some buildings need to use trees. In ancient times, forest resources were very scarce, and it was difficult to find materials for burning fire, let alone wood in Gai Lou. Some people who have been poor for a long time are even going to cook with cow dung and sheep dung. The most serious thing is that there are few trees left around the city since the Sui and Tang Dynasties. In order to cook, the rural people cut down all the mulberry trees that can be used, and some even cut down jujube trees to cook. This is already the case in the countryside, not to mention the city people. The difficulty of cooking can be imagined, because many people can't afford firewood, the tools for cutting firewood are idle, and sometimes they even see the dilemma of burning fire without firewood on the battlefield. In the Tang Dynasty, in order to distribute goods to officials, only two Jin of charcoal fire was used to cook every day, and even officials were already suffering to this extent. However, the hard days have finally come through. Later, not only did coal replace wood, but now there are more gas and natural gas, which are very convenient to use. More forest resources can be used for more needs, and people don't have to worry about cooking.