To let the people more understand what is "Qi Men Dun Jia 奇門遁甲", I just use my answer for Collette Chin's question on May 27, 2013 in facebook and make it as individual article.
When you learn any Chinese Metaphysics, first thing first is understood the main purpose for this kind of Chinese metaphysic. Although when you are good in that kind of Chinese Metaphysic, you can extend the use to the other kinds. Such as I taught my student to use Face Reading for Feng Shui, for Bazi or Augury, but its main function is Face Reading, that is what we call it in Chinese “通變”.
Qi Men Dun Jia mainly for battle use, it is a kind of war strategy; you can learn it from Master Hung Ming in Tri-Kingdoms. It includes two parts, one is Shut術 and other is So數, nowadays, most people know are the So術 only and not Shut術 because it had loss already.
To proof what am I talking is correct. Just bring you to read 2 Chinese articles, then you will know whether those masters’ teaching that Qi Men Dun Jia is real or not???
名人軼事
◎阿文成兵法
阿文成征金川,一日安營已定,忽傳令遷移,諸將以天晚力阻,公隨發令箭 云:違者立斬。合營雖從之,而不免怨誹。迨昏夜大雨,前此營基,水深丈余, 幾為漂沒,咸詫為神奇。公曰:“我有何異術,特見群蟻移穴,知地熱將雨耳。”
按文成此舉,不難于先見,而難于實言。稍有權術者,必又以為遁甲奇門矣。健兒雖莽,肯受吾紿?
From the above article, you can see that most of the ancient Generals were studying Qi Men Dun Jia.
閱微草堂筆記 --- 紀曉嵐
奇門遁甲之書,所在多有,然皆非真傳。真傳不過口訣數語,不著諸紙墨也。
德州宋先生清遠言,曾訪一友(清遠嘗舉其姓名,歲久忘之。清遠稱雨後泥濘,借
某人一騾騎往,則所居不遠矣。),友留之宿曰:「良夜月明,觀一戲劇可乎?」
因取凳十餘,縱橫布院中,與清遠明燭飲堂上。二鼓後,見一人越垣入,環轉階前
,每遇一凳,輒蹣跚,努力良久乃跨過。始而順行,曲踴一二百度;轉而逆行,又
曲踴一二百度。疲極踣臥,天已向曙矣。友引至堂上,詰問何來,叩首曰:「吾實
偷兒。入宅以後,惟見層層皆短垣,愈越愈不能盡。窘而退出,又愈越愈不能盡。
困頓故見擒,死生惟命。」友笑遣之,謂清遠曰:「昨卜有此偷兒來,故戲以小術
。」問:「此何術?」曰:「奇門法也。他人得之恐召禍,君真端謹,如願學,當
授君。」清遠謝不願,友太息曰:「願學者不可傳,可傳者不願學,此術其終絕矣
。」意若有失,悵悵送之返。
From the above article, you can see the Scholar Kay recorded about the real Qi Men Dun Jia was lost.
I don’t think those masters who teach this subject have read these 2 articles. They are only making it as a product to sell it to the public only.