Architectural Art of 9

Architectural Art of 9
In ancient China, odd numbers were called positive numbers, and even numbers were called negative numbers. 9 is the biggest positive number, so 9 was used to show the imperial authority. The number of fences and steps of Circular Mound Altar is either 9 or a multiple of 9. The Circular Mound Altar has three layers. The upper layer consists of fan-shaped stones, a total of 9 circles. The innermost circle has 9 stones. 9 pieces of stone were added progressively for every circle to the outside. The sum of the diameter of the three layers is 45 (9X5) Zhang (135 meters or 443 feet), symbolizing the so-called ‘Nine-Five Dignity’ of the emperor.