1. The territory of the Song Dynasty encompassed an area of 2.8 million square kilometers.
2. The Song Dynasty was divided into the Northern Song and Southern Song periods. During the Northern Song, the territory reached its maximum size of 2.8 million square kilometers, with a peak population of approximately 130 million. In the Southern Song, the largest territory was about 2 million square kilometers, with a peak population of around 80 million.
3. By comparing the population density per square kilometer across different dynasties, the following averages were observed: Han Dynasty: 10 people, Sui Dynasty: 11 people, Tang Dynasty: 7 people, Ming Dynasty: 12 people, Qing Dynasty: 30 people, Northern Song with the defeated Jurchen: 46 people, Southern Song: 40 people.
4. The Song Dynasty witnessed a historical peak in population numbers, which can be attributed to the ancient society's view that population equated to productivity. Consequently, every dynasty implemented policies to encourage childbirth.
5. Constraints on population growth typically included war, famine, and additional factors such as the limitations of food production.
6. During the Song Dynasty, Confucianism was revitalized, Neo-Confucianism was founded, and technology advanced rapidly. The political climate was relatively open, free from severe eunuch privileges and warlordism. The frequency and scale of palace coups and peasant rebellions were comparatively low in Chinese history.
7. In the Northern Song period, the rapid growth of the population, from 3.71 million in 980 to 12.6 million in 1124, was attributed to the introduction and promotion of the rice variety from Champa.
