Main purpose and application
As what I wrote on the first article about QMDJ is used for the war, I have already quote some history to proof my point of view. If you learn this subject from a master, they would tell you how did the QMDJ coming. May be I am repeating it again here.
Our first king, Wong Tgai (黃帝), fight with his enemy, Chi Yau (蚩尤). The war was going on for a period of time. It was because Chi Yau (蚩尤) had a strong and powerful back magic to support. Our king was pray to our God and wished to get some help from spiritual side. Our God show him the Tin Gon (天干) and Day G (地支)on the sky. And also send the Queen of Wind 風后to teach him the Qi Men Dun Jia 奇門遁甲. In additional, our clever king also invented a Compass trolley, Winning became the end result.
From this short legend, you can see the QMDJ appeared at the war, of course we apply it in the war will be more appropriate. Beside it, our king was using it for overcome the back magic, if you use it for protection, it will be wonderful.
If some of my audiences who are practice Taoism, you may heard or practice about hide your spirit and soul (藏魂、藏魄)method. Then QMDJ is good for it also. You can find one of the Taoist, Got Hung (葛洪), who also good in QMDJ.
Today we have pandemic of Covid-19, if you know QMDJ, you can apply it to reduce the risk to catch this virus. Good luck to all of you!