Traditionally the Reiki Ryoho (typically stated in English as "symbols") were passed down from master to student in secrecy. Reiki students themselves were not allowed to keep written copies of the symbols, rather they would need to have them committed to memory. The publishing of the Reiki symbols in print and on the internet is the subject of much controversy among practitioners. Some feel that traditions of Dr. Usui (the founder of Reiki) should be honored while others feel that the characters on their own do not hold power to those who have not undergone a Reiki attunement with a Reiki master.
In respect for my Reiki teacher and own personal beliefs, I will discuss the Reiki Ryoho but will not publish them. They are easily found though.
The first symbol: Cho Ku Rei
The power symbol. A Reiki practitioner would use this symbol to increase the power of their healing. The symbol has many stand alone uses (cleaning negative energy, on the spot treatments, spiritual protection, etc.) and can also be used in conjunction with other Ryoho to enhance their power.
The second symbol: Sei He Ki
The symbol for emotional/mental harmony. A Reiki practitioner would use this symbol for calming the mind or emotions and to promote healing of such areas. The symbol clears emotional blockages, balances the spirit, and heals past traumas.
The third symbol: Hon Sha Ze Sho Nen
The symbol for distance healing. This symbol is used when a Reiki practitioner sends healing to a client who is in another area. The symbol can be invoked to promote healing in the past, present, or future.
The fourth symbol: Dai Ko Myo
This is the master symbol of Reiki and the most power of the Ryoho. It is only used by Reiki masters. It signifies intelligence and wisdom and can be used to heal the soul.