Knowledge extension:
Bama Yao Autonomous County, which belongs to Hechi City, Guangxi Zhuang Autonomous Region, is located in the northwest of Guangxi, bordering Dahua Yao Autonomous County in the east, lingyun county and Youjiang District of Baise City in the west, Pingguo, Tiandong and Tianyang counties in the south, and Donglan and Fengshan counties in the north. It has a subtropical monsoon climate, with high terrain in the northwest and low southeast, and few mountains in the territory. It is known as "eight mountains, one water and one farmland" and its land is very precious.
Bama is known as the hometown of longevity. According to the second national census in 1964, there were 28 elderly people over 100 years old, 50 in 1982, 69 in 1990, and 79 in 1994, accounting for 3.50% of the county's total population. In the fifth census in 2000, there were 530 people over 90 years old.
According to the Bama county government, the external environmental factors contributing to Bama's longevity are geomagnetism, air, water, sunshine and food. These five factors correspond to the five elements of yin and yang in ancient geography, namely, gold, wood, water, fire and earth. Geomagnetism corresponds to gold, which is the head of the five elements and the source of all things. According to reports, the geomagnetic field in the general area of the earth is about 0.25 gauss, while that in Bama is as high as 0.58 gauss.