Dai KO MYO enables recognition and clarity about your true path. There is less written about this Reiki Symbol and function than about the others in the context of Reiki because until quite recently there have been very few Reiki Masters who are empowered to use it. It is still somewhat unexplored. Mrs. Takata drew the Symbols differently for many of her students. The First three Symbols were compared and one form for each was selected after her death. This was not done with the DKM so there are many different versions which you might encounter. They all work.
DKM activates a powerful energy for Self-Empowerment and is used for opening Spiritual connection and intuition and cellular healing. Once you are attuned for this energy you can use it for treating yourself and others each time you activate Reiki. It is said to work at the cellular and genetic levels and is valuable for treating Migraine Headaches. Many people have found that Level three Reiki Attunement increases the intuitive and psychic awareness that they can comfortably access.
I have heard this called the vocational or life purpose function because it often seems to initiate dramatic changes in career and lifestyle. It is also used as Manifestation energy by some as is Cho Ku Rei the power boost from Second Degree Reiki. To use DKM for manifestation you activate this energy and clearly visualize what you intend to manifest this will not bring you things that are not in accord with your high self and soul purpose.