Medic Sealing Art: Transfusion Seal

This is a special fuinjutsu created by Izaku Osawa to carry large quantities of blood on the battlefield with reduced risk. It was later studied and improved by Hideyuki Ohara, who had quickly become a revered master of the technique. Lesser versions are now taught to Ame's special forces and various high-level medic-nin. In the right hands, this technique is one of a medic-nin's most powerful lifesavers.

After weaving the needed hand signals, the user uses special ink to write a circular symbol on their bare skin, preferably their palm on wrist and channels their chakra into a packet of blood needed for transfusion. The blood then travels from their container into the seal on the user, filling up the seal until it is colored red. This seal enables the blood to remain warm and ready for transfusion without being tampered or sabotaged by outside forces. The seal prohibits the user's body from tampering with the blood until it is needed, even if their own blood touches it, therefore keeping the blood clean. The seal is capable of holding up to twenty pints of blood without risk to the user. When ready for transfusion, the blood is released through the palm into the target via another seal pre-written on their body. The user can also keep the seal for themselves by occasionally adding blood to their seal and giving themselves transfusions when their own blood is low. Hideyuki Ohara has been stated to have once wielded up to four seals on each arm during heavy conflicts when transfusions were critically needed.

However, this technique requires great chakra control and sealing knowledge. If this technique is used without proper control, the blood could either be lost through the weakened seal or even overflow the user's own body, leading to death. Other risks include possible contamination to the blood. To lower the risk of such mistakes, it is best to learn the technique gradually with smaller units of blood and practice until a certain mastery is reached. Also, the blood type in each seal must be memorized to prevent transfusion disasters with those of an incompatible blood type.