Souzou Saisei is a Ninjutsu technique developed by the Sannin Tsunade. It is said this technique will prevent Tsunade's falling in battle. Over time Tsunade will concentrate chakra to a spot on her forehead that takes the form of a diamond. When she releases the seal on the jutsu, the chakra disperses and stimulates the proteins of her body to increase the speed of cell division and reconstruction of cells. This allows her to recreate all organs and tissues. The technique itself does not regenerate the old cells, rather it hastens the creation of new ones through division. Unfortunately a body's cells can only split a certain number of times in a lifetime. By speeding up this process Tsunade is shortening her life. She may not die in battle, but she can die by speeding up its natural lifespan.