How to understand the Ninth Five-Year Plan? thank you

In ancient China, numbers were divided into positive numbers and negative numbers, odd numbers were positive and even numbers were negative. Nine is the highest yang number, with five in the middle, so "nine" and "five" symbolize the authority of the emperor and are called "the respect of the Ninth Five-Year Plan".

Another view is that the word "Ninth Five-Year Plan" comes from the Book of Changes.

The handed down version of the Book of Changes is said to be played by Zhou Wenwang, so it is also called the Book of Changes. The first of the sixty-four hexagrams in Zhouyi is the dry hexagram, which symbolizes the sky, so it becomes the hexagram representing the emperor. The dry divination consists of six Yang divinations, the anode and the prosperous pole. Counting from the bottom up, the fifth one is called the Ninth Five-Year Plan. Nine means that this plan is a positive plan, and five means the fifth plan. The ninth five-year plan is the best of the dry hexagrams, which is the first of the sixty-four hexagrams, so the ninth five-year plan is the first of the sixty-four hexagrams and the first of the three hundred and eighty-four hexagrams, which has become the emperor's phase. The "nine" here is not a specific number, but a symbol to distinguish the yin and yang attributes of numbers. Later, people used "Nine" and "Five" as specific figures, thinking that one was to fit the "Ninth Five-Year Plan" representing the emperor; Furthermore, the use of the numbers "nine" and "five" in architecture is also in line with aesthetic principles. The paraphrases in the Book of Changes include "the change of the avenue, each with its own destiny, is conducive to maintaining harmony and chastity". The origin of the name of the Hall of Supreme Harmony is said to come from this.

Zhouyi, one of the oldest classics in China, has always been regarded as the first of the six classics, which has a far-reaching influence on all fields of the Chinese nation. Therefore, it should be more credible that the word "Ninth Five-Year Plan" originated from Zhouyi.