According to tradition, the Usui Reiki symbols are held sacred and should be kept confidential only to be revealed to those receiving attunements to these symbols. The power of the symbols comes only from the Reiki attunement. The names and drawing of the symbols should not be discussed with anyone not attuned to them.
Of course, with the Internet, it is simple to find information about the symbols. They are no longer secret ... not everyone holds them sacred.
One reason for the secretiveness involved with the symbols is respect for their sacredness. Another reason is that, without an attunement to the appropriate level and the associated symbols, the symbols are useless; why bother to give them to someone, making them believe that they are receiving something of value when they are not? A third reason is that, in my belief, a person becoming familiar with the symbols before attunement to them may have special pre-conceived notions about them and miss some of the subtlety of the energy inherent in them. I believe this last reason to be the most important. As the symbols are, in my opinion, to be used for the greater good and not for any special agenda, the feel that one develops for them is very important in grasping the meaning of them. I feel this so strongly that, in my teaching, I attune the students, teach them the symbols, let them feel them, and then discuss them.
To me the symbols behave as intelligent life forms. In fact, I often consider the different types of Reiki symbols to be different types of healing angels with different personalities and talents. This is a very good reason, in my mind, to give them the respect due all intelligentenergy forms.
I read in many places how certain variations, sometimes differing radically from the traditional, of the symbols are more powerful. I tried some of these variations and usually found them to have little or no power for me. Maybe it's because I haven't been attuned to them. I've quit experimenting with these symbols because of the time wasted with no revelations other than they don't work well for me. From my understanding from several spiritual traditions, some symbols may have power of their own and, unless one knows and fully trusts their source, it is unwise to trifle with symbols. I now use only the symbols I am attuned to.
I believe most variations in symbols are valid. The symbol that you are taught and attuned to is the symbol you should use. If it varies from published material, stick with what your Reiki master taught you. In my experience, even slight conscious variations from what I was taught seem to weaken a symbol's effectiveness but unintended errors seem to be no problem. Some of my symbols seem to be slight variations of anything I've found published anywhere but are effective.
The Power Symbol feels to me like strength and protection. At first, I associated this symbol, in distant healing, with injury. More experience teaches me that this symbol can also be associated with the need for protection and strength. It seems that strength and protection are more closely associated than I originally assumed. I often wrap the receiver of a distant healing in a Power Symbol at the end of the healing to seal the healing. I wrap my vehicle in a Power Symbol while driving.
The Mental/Emotional Symbol is often associated with emotional trauma of some sort. When associated with a physical trauma, there is usually an emotional component that may not be immediately obvious. When left to work on its own, this symbol seems to most often go to the heart or throat chakras but will go where it is needed. As it seems a very calming symbol, I send it to upcoming and past situations. I send it to impending storms. My vehicle is always surrounded by them. I always send the Mental/Emotional Symbol with the idea that the calming energy do the most good for the situation, not necessarily what I feel to be the most good.
I find the Distant Healing Symbol extremely gentle yet strong. It is the one symbol that I cannot send with power behind it. It seems to blast out and instantly slow itself down to a gentle drift, kind of like throwing a feather.
Although I usually ask permission to send a healing on the spiritual level, I sometimes forget. The Distant Healing Symbol comes back gently if the healing is rejected. Sometimes the initial contact in using this symbol is quite emotional; very real contact is made.
From the gentleness of the symbol I associate with it, I classify the Distant Healing Symbol as a gentle, friendly, loving touch. Nearly everyone likes and needs to receive this symbol. At times I will send the Distant Healing Symbol for several minutes. It is very calming and soothing and, sometimes, it is the only symbol that is wanted.
The Distant Healing Symbol transcends time and space. It can be sent anywhere to any time. It can even be sent into past lives. It is used as the opener and allows the other symbols to be sent to any time or place. It is very underrated, I feel.
Another interesting feature of the symbol is its almost diagnostic properties. When I draw the symbol on someone, either physically or during a distance healing, I find an area over which I have trouble drawing the symbol and can't remember which line comes next is a part of the body in need of attention. I repeatedly draw the symbol over the person. With repetition, the symbol, drawing becomes easier and the pain is relieved. I find this to be especially true in cases of minor injury like a sunburn or sprain.
The Usui Master Symbol is very interesting as it appears to be the symbol that connects and moves one to the spiritual plane. It even looks likea temple. The symbol apparently balances the feminine/masculine energies in a person. Sending this symbol to or physically drawing it on someone seems to have tremendously relaxing effects. This is the symbol that everyone seems to settle into after receiving the others. If I start with this symbol, the receiver usually doesn't want to change to another.