Huyền Ca, Huyền (玄, pinyin: Xuan) is Mysterious, Ca(歌) is read from Cơ(机, Ji). The noun means The Mysterious Engine, The Heaven’s Secret, The Miracle of the Creator, The Mysterious Cycle. Due to its secret and mysterious nature, Xuan Ji is not supposed to be disclosed to the ordinary person unless it is heavenly instructed for moral purposes. Lord Master said: “The Mysterious Tao is hard to find” or “I teach until the Tao of Heaven’s Engine has been well understood.” (“Câu Đạo lý cơ huyền khó kiếm” or : “Thiên cơ Đạo lý để lòng mới thôi”).