"Use Jiu" appears in Qian hexagram: seeing a group of dragons without a head, it is auspicious.
"Use Six" appears in Kun Gua: Li Yongzhen.
In fact, the whole " Yijing " is about the changes of using nine and using six. Nine is Yang, six is Yin.
If you think using nine is used on the Qian hexagram and using six is used on the Kun hexagram, then you are very wrong.
First of all, you need to understand what this "use" means. This use means "function", and tell you the functions and functions of the Qiankun hexagrams. Only when you know the function can you know how to use it rationally.
Why do you need to know the usage of the two hexagrams of Qian and Kun? Because the intersecting of heaven and earth and the interaction of yin and yang have all things. Everything is the product of yin and yang. All things are complex and people have different temperaments, which are all manifestations of different degrees of yin and yang. Therefore, only the two hexagrams of Qian and Kun can be used as the words of Nine and Six.

Qian hexagram has six lines, which tells you the six characteristics of yang energy, hidden dragon, seeing dragon, vigilant dragon, jumping dragon, flying dragon, and arrogant dragon. The "Use Jiu" line saying: Seeing a group of dragons without a head is auspicious. It is to affirm that the use of each line is different. However, as yang energy, all have the same fundamental characteristic, which is "self-improvement".
"Use Nine" means telling you the function of yang energy. So under what circumstances should you use yang? It is when the yin energy is heavy. So you will find that people with heavy yin energy are very hard-working and hardworking. No matter where he is, even if he is a leader, he still has to work hard.

"Use six" means to tell you the function of Yin Qi. Kun hexagram also has six lines, but its function is the same, to maintain integrity, so the line "Use six" says: "Li Yongzhen". As a yin characteristic, it is "a great virtue carries things." "Use Six" means using it when the yang energy is heavy. The yang energy is heavy and often arrogant and cannot tolerate others, so it is necessary to remind him to "be kind and carry things with virtue."
The problem is here, then do you know the yin and yang attributes of the sixty-four hexagrams?